I could take on each assertion of simplicity case by case. But pushing back against claim after claim that biology is a simple answer to some contentious problem makes me feel like the poor king in Royal Match, who hopes that by matching the right tiles the game player will prevent him from being impaled by an ever advancing wall of spikes . So I have decided to try a different tactic: over time, with intermittent short posts, I will describe some example of biological complexity. Some examples will be about sex, gender, secuality or race; others some feature of basic biology or evolution. As the examples accumulate maybe I can change thought habits so that for more and more people the go-to starting point will be: “biology is complicated and simple explanations are unlikely to be true”!

In this episode I report on recent findings about human evolution. Geneticists have been studying small regions of DNA found in individual human genomes (the totality of DNA in the cell nucleus of each individual). They playfully call these DNA segments “ghost DNA”, remnants (and reminders of) ancestral dalliances between modern humans and archaic human relatives or between different evolutionary lines of non-modern hominids.

In the beginning, as it were, scientists envisioned human evolution as a linear process. Ancestor A preceded ancestor B, then C. At some point Homo sapiens took charge, migrated out of Africa and spread around the world. As scientists found more and more protohuman fossils, it became clear that some were side branches and linearity gave way to bushiness. But still the idea was of forward progress. This diagram from the Museum of Natural History offers a visual.

Notice especially the top tier—less than a million years ago. Homo sapiens, the Neanderthals and a group called the Denisovians are all around at about the same time, and are thought to have branched off from a common ancestor. (This will no doubt change with new findings of fossils and new methods of analysis, but it is what we know at the moment). Anyway these groups are illustrated as existing in pristine parallel.

But we have known for a while that modern humans mated with Neanderthals and with Denisovians, and now it appears there were other mystery ancestors—the ghost ancestors. And there was quite the back and forth, as shown in this diagram.4

Source: https://www.nature.com/articles/nature.2016.19394

Findings since this 2016 diagram show an even more complex picture. Human and protohuman populations have mixed frequently and way farther back in ancient human history than had been imagined. As researcher Priya Moorjani said, “We often think of human evolution as a branching tree, but new genomic data and analytical methods reveal a much more interconnected history — more like a complex web of populations connected by repeated episodes of migration and mixing.” (1)

The above diagram, which dates from 2016 shows more recent (i.e. 60-100,000 years ago) intermixing between several lines of human ancestors. It is less a branching bush and more of a net or mesh.

Since 2016 researchers have traced the ghost mixing back even further—closer to a million than 100,000 years ago. More canoodling, earlier than previously realized, and with greater varieties of ancestors.

The above illustration depicts that despite an early branch in the human lineage that took place a bit over 700,000 years ago, individuals from separated branches interbred. Then again, half a million years ago they interbred again. Then a quarter of a million years ago, members of the main hominid line back bred with at least one of the more recent branches and a mere 29,000 that line bred again with modern Europeans. So far this is what we have evidence for. I have little doubt that those big time gaps will shrink and the number of data-backed inter-group mating events will increase. Intermixing, it seems has been going on for nearly a million years, a finding which make the idea of “racial purity” ludicrous. And they highlight human evolution as a premier example of evolutionary complexity.

A bit of background is in order, and of course it starts with Donald Trump and institutional cowardice. As soon as he took office, Trump froze millions of dollars in Federal grant money that Harvard faculty members had earned for peer reviewed research projects. Supposedly Harvard stood firm and the government backed down and reinstated the grants. But that was a cover story. Internally Harvard began a process that we can, with a straight face, call white-washing, and also gay and gender diversity cleansing and more.

On April 28, 2025 Harvard rebranded its “Office for Equity, Diversity, Inclusion, and Belonging” as the “Office for Community and Campus Life”. They also announced that the University would no longer host 10 so-called “affinity graduations”. Affinity graduations allow students with similar national, racial, gender or sexuality backgrounds to celebrate their accomplishments as a group. It is an add-on, not a replacement for the all-inclusive official, degree-granting ceremony. With so little notice a scramble ensued, but eight of the ten celebrations that Harvard had hosted on campus in 2024 managed to find off-campus venues and financial support for some festive decorations and a reception. The groups included Black, Latino, first-generation, low-income, LGBTQ+, Muslim, and Asian, Pacific Islander, and Desi American (South Asian-American) graduates, as well as veterans and people with disabilities. 1

This year, 2026, with more time to plan and fundraise, the same eight again held off campus affinity celebrations. I was honored when the student organizers of the LGBTQ+ group invited me to be one of two keynote speakers.

Here are my remarks.

I have to start by congratulating all the graduates. You have worked hard to get to this point, and what an achievement! You deserve joy, praise and camaraderie; I offer you all of this and hope that you will offer the same to one another. The parents and families of today’s graduates also deserve congratulations. For loving and encouraging your children, for making all the efforts and sometimes sacrifices—the ones that sometimes only you know about-- to help your child reach this goal.

As a teacher, I always found myself sad and exhausted by the end of graduation day. Just as you have worked hard for four years, we teachers do our best to contribute guidance, encouragement, knowledge, and the occasional nugget of wisdom to your journey, and finally, on graduation day, to wish you well, and push you over the threshold to the next phase of your lives. For you it is the start of a new phase of life. For us, a parting. So, I also want to congratulate all your teachers who have worked harder than you may realize to help you to this point. Each one of you is the result of a massive group project, people! And YAY for the entire collective.

Now let’s turn to that giant elephant in the room. This is the second STUDENT LED Lavender Graduation (at least since the mid 1980s), and I am very proud to have been asked to speak at this historic event. The bad news is that in these difficult times, the institution of Harvard University has lost both its nerve and its moral center by backing away from official support for, and celebration of student diversity. The good news is that Harvard’s students have stepped into the breach. You have discovered the empowerment of working together, face to face [it really beats relying on social media] on a common goal. You have organized an event for yourselves, and discovered that there are non-Harvard institutions, such as this awesome and historic Church, that embrace you and offer you shelter. The world is much larger than Harvard.

Of course it is not just Harvard. The entire nation is having a moment. We are moving from a time that we had come to think of as normal, a time when institutions seemed to embrace diversity, equity and social justice, to the post normal, when it appears as if we are picking our way through ideological quicksand. Suddenly, but not suddenly, word meanings have taken on an Alice in Wonderland quality. The government defines those who support diversity as discriminating against straight people, or cis people, or white people, or—let’s just say it—against straight white men. Assuming that most, if not all of you at some time in your life read Lewis Carrol’s Through the Looking Glass, this craziness should be familiar. I often turn back to this conversation between Alice and Humpty-Dumpty:

“`I don’t know what you mean by “glory,”’ Alice said.

Humpty Dumpty smiled contemptuously. `Of course you don’t-- till I tell you. I meant “there’s a nice knock-down argument for you!”’

`But “glory” doesn’t mean “a nice knock-down argument,”’ Alice objected.

`When I use a word,’ Humpty Dumpty said in rather a scornful tone, `it means just what I choose it to mean--neither more nor less.’

`The question is,’ said Alice, whether you CAN make words mean so many different things.”

Inverting the meaning of words such as bias and discrimination is shocking, but as Humpty-Dumpty themselves pointed out we can assert control over the matter. If we have now entered into a post-normal era, I am old enough to have lived in the pre-normal, before there was any institutional support for studying gender/sex and sexuality, before there were programs to help gender non-conforming children to live their lives in the open, before it was normal to admit more than 10% women, 5% Jews or even fewer people of color to a new medical school class. Before Harvard had any women or people of color in the rank of full professor. There were no institutional structures to promote or protect us.

So we had to build our own. We followed an already-worn path. For every (all white) American Medical Association (founded 1847), for example, there was a National Medical Association for African American Physicians (Founded in 1895) dedicated to equitable medical treatment. In the 1890s American institutions such as Harvard, Johns Hopkins, and the Smithsonian supported tables for American (white, male) scientists’ to carry out research at the Naples Zoological Station. By the 1890s a group of women scientists had banded together and funded the Naples Table Association for Promoting Laboratory Research by Women, and sent numbers of women off to Naples to study marine biology alongside the men. The built their own institution to circumvent ones that rejected them.

Speeding into the late 1960s, when no official sources existed to teach women about their own genital anatomy—we (this was MY generation) got speculums and mirrors and looked for ourselves!! We wanted the truth about menstruation and other health related questions. And so a group calling themselves the Boston Women’s Health Collective got together and wrote a pamphlet called “Women and their Bodies”. I sold the New England Free Press newsprint first edition for $.75 on a Providence, Rhode Island street corner. A large carton sold out in less than an hour. Only later did Knopf, a mainstream publisher, pick it up under the name “Our Bodies, Ourselves” . This was happening during the same time period that the Black Panther Party founded and operated the People’s Free Medical Clinics, which offered first aid, childhood vaccinations and “screenings for high blood pressure, lead poisoning, tuberculosis, and diabetes.“

Meanwhile, back at Brown University group of about 5 assistant (untenured) professors, unsupported by any dean or department, designed and taught Brown’s first introductory women’s studies course, and the students came. One of us, Louise Lamphere, later sued Brown for tenure denial, a class action suit on behalf of all women, and ushered in the era you now know, in which there are many women faculty including, even full professors, and university presidents. The process at Harvard was a bit slower (not that I am competitive on behalf of my home institution-LOL) and was student-initiated. In 1978, responding to student petitions, Dean Henry Rosovsky established the Committee on Women’s Studies, which encouraged the development of departmental courses in the field, and in 2003 this committee became a degree-granting department –the Committee on Degrees in Studies of Women, Gender, and Sexuality (WGS).

And so, gradually, we entered an era of plenty; one in which it seemed to make sense to fund an entire school on soft money. One in which it was taken for granted that public health is a social good. One in which Universities officially celebrated diversity—with women’s centers, centers for African and African American Research, Queer Students Association, SHADE, Trans Harvard and more. The NIH funded medical research that focused specifically on minority lives and experiences. Affirmative care became the treatment norm, and young children could socially transition with the support of parents and schools.

But now we face intense pushback. I will put it up front that this change is painful and sometimes bewildering. But we have a history. WE—minority citizens and their majority allies-- built the era of plenty and acceptance that is now under attack. And we can reconstruct a new era, returning to our older practice of building our own structures and charting our own paths. The good news is that there are a lot of us (many more than in olden times!) and we are already organized.

For example, I follow a simple listserv, founded after the 2024 Presidential Election, that has become a hub for information exchange—about funding opportunities, jobs, how to write a grant that can slide through the AI screening process; this same listserv functions as an organizing center that can gather forces to prevent a takeover by anti-trans medical workers at a professional meeting, or recruit data scientists to a LGBTQ Data Rescue Hackathon; and more.

Despite the Quisling-like collaboration from official circles at Harvard, Columbia, Penn and elsewhere, not all structures are wrecked. Before the backlash took on full force, for example, a number of new scholarly journals came into being, each dedicated to improving knowledge about gender and sexuality. Professional societies focused on LGBTQI health and well being already exist. Far from building from scratch, I think we are in a stronger position than I at, least at first, had realized.

As shocking and painful as they are, the current assaults on our communities also present opportunities— to pursue our own interests, develop new theory, and ready a successor science of gender and sexuality to seize the next moment---the one that comes after the counter-revolution has been defeated or at least restrained. This is the opportunity that you, the graduating class can seize and run with. You can complete the disrupted databases, further develop the ideas, the methods, the clinics and social services which we have already begun, and which we never stopped working on. You can use your capacious imaginations and your fresh perspectives and abundant energy to imagine new ways of moving forward, maybe even ways that are a bit more armored against the kind of backlash we are currently experiencing.

This may be a bit obscure, but I started my science career studying insect development. Insect eggs hatch into larvae, which eat, grow and shed their skin to become larger larvae. Eventually the larvae stop moving and eating. They grow hard shells and their functioning parts disintegrate. I think of this as analogous to the hardening and dissolution of the fascist elements currently devouring our nation. But all along, inside the larva, discrete collections of cells—the imaginal discs—have been planning their takeover. In fruit flies there are genital discs, and wing discs, and thoracic disks and three pairs of head discs. And these organized groups of cells join forces to build a new structure—a successor structure—the adult fly, butterfly, moth etc. So as I watch each of you receive your Rainbow Stole, I am going to picture you, this beautiful group of LGBTQI graduates, as imaginal discs transforming from your Harvard sojourn into whatever beautiful butterfly, moth, honeybee, lady bug, dragonfly, darning needle, or other soul you will inhabit during this next phase of your life. You have been quietly and methodically building this new self, and I know that it will be amazing and possibly earth-shaking. My best wishes to you all!

I suspect that some readers are frustrated by my expressions of hope. Rightfully, they note the damage that has been done and understand how much repair work we face. I don’t deny these truths. I am not, as my grandmother Mrs. Malaprop once famously said during a family discussion, an ostrich. I do not stick my head in the sand when I see the handwriting on the wall.2 But focusing only on the terrible things foments despair. Being just as realistic about how to hope, gives us the power to change. Resist! Yes, of course. But build forward so that we will ready a better future. And who better to do it than all those high energy, smart twenty-somethings who have just left college and are making their way into the world?

In case you have been losing sleep over this question: male sea horses have an X and a Y chromosome, and females two Xs. Copacetic, right? But… XY sea horses (and also pipefish and sea dragons) brood eggs and give live birth to their young. To accomplish this feat, during their adolescence XY seahorses develop a brood pouch, and when XY and XX mate, the XX deposits the fertilized eggs in the pouch. This triggers physiological changes which have much in common with how the placenta forms and functions during human pregnancy. The pouch wall thickens, and blood vessels grow like crazy. Even the RNA profiles, which reflect which genes come alive to promote cell and blood vessel growth of the pouch/placenta/uterus, are similar.1

Even though the embryo-supporting tissue in human XX’s resembles that found in sea horse XY’s, the molecules that trigger placental development differ. Human XX’s deploy estrogens, while sea horse XY’s make use of what they have on hand—in this case androgens such as testosterone. One bit of evidence that seahorse androgens stimulate the expression of genes specific to pouch/placenta formation emerged when experimenters treated XX sea horses with androgens and observed that they developed brood pouches. In binary-challenging terms, when treated with testosterone, female sea horses, which do not normally brood their young, develop a pouch that potentially could brood young.

Leaping Lesbian Lizards! Or, a detour about language

Using the terms male and female, rather than my choice here, to refer to XX and XY beings, leads to conceptual trouble. In the above experiment, researchers struggled with their categories. One group wrote “The brood pouch, like the mammalian placenta, performs the functions of gas exchange, waste removal, and osmoregulation”, and then that it is “rich in blood vessels, suggesting father-to-embryo interaction through epithelia on the lumen, similar to mother-to-embryo interaction in mammalian placenta.” 2 So why, then, do researchers refer to the XY brood pouch that is so similar in form and function to the human placenta as a “pseudo-placenta”? Looks like a duck. Quacks like a duck. Can’t we just call it a duck?

Before answering that question let me offer one other example in which scientists struggled to find the right words to describe aspects of sex biology in situations that were—well—non traditional. Parthenogenetic, all-female populations of whiptail lizards are common in arid areas of the southwest United States (and elsewhere in the world). Now when I say parthenogenetic, I mean that before an egg-producing indvidual—which I will refer to as the female—releases an oocyte from her ovary, the oocyte doubles its chromosomes, giving the egg 4 chromosome copies. Upon ovulation the four reduce down to two copies—the diploid number needed for embryonic development. For readers who remember their biology lessons, the more technical version reads: the egg of a female whiptail from an all female, parthenogenetic population first becomes tetraploid, and then when ovulated it becomes diploid. Finally, carrying her diploid eggs, the lizard manages to activate development without stimulation from a sperm (as would happen in a mixed-sex population).3

Now comes the fun part. Quack Quack. To stimulate ovulation, one female mounts another and wraps her tail underneath so that, just as with male-female lizard copulation, their cloaca’s rub together and touch. When observing heterosexual lizards observers sometimes refer to this behavior as a cloacal kiss4 during which a male transfers sperm from his cloaca to hers. Except for sperm transfer, female-female mounting , cloacal touching, the stimulation of egg release, and the accompanying hormonal responses looks exactly like heterosexual copulation. But the scientists who first observed the phenomenon could not manage to call it that. So “pseudocopulation” it became.

There are other examples but the bottom line is: in the 20th century scientists thought of sex as an absolute binary. (Some still do). If an individual was a male, then it only had male body parts, male hormones and its body did male things. In the face of organisms that broke rank with absolute binarism, scientists had no recourse but to reach for “pseudo”. It was bad enough that the XY/male seahorse brooded and gave birth to the family babies. But a placenta? By definition, a male just can’t have one. So the one that it did have had to be a pseudo-placenta. The same reasoning held for a female-female copulation in lizards. By defninition copulation had to be a heterosexual act—so that thing the female lizards do, which is exactly the same thing as a male-female couple, minus some sperm, has to be pseudo. If you remove the binary framework, however, then XY seahorses have a placental structure in their brood pouch and parthenogenetic female whiptail lizards copulate with each other.

I say XX or XY, call a placenta a placenta, and heterosexual or homosexual, whiptail lizard copulation is copulation. Quack, quack.

A note about evolution

These stories, while fascinating per se, also tell us something interesting about how a binary framework can interfere with understanding the evolution of non-binary biological phenomena. Inserting the prefix “pseudo”masks the fact that evolutionary processes regularly produce gender-bending anatomies and behaviors. The human placenta and the sea horse brood pouch have much in common and their anatomical similarities enable each to nurture fertilized eggs and then give birth. If you stop worrying about gender, this is merely an example of convergent evolution—the independent evolution of the same or similar traits in barely-related species. The development of placentae and brood pouches are triggered by steroid hormones that are sometimes misnamed “sex hormones”.5 During the evolution of the placenta and the brood pouch, the body grabbed already-available building material—for the placenta that meant estrogens (and other reproductive hormones) in humans and androgens (and some of the same reproductive hormones) in sea horses. Evolution is a scavenging mother-f***er and it is not wedded (as it were) to binary sex structures.

Evolution also reuses (conserves) the available genetic material. Seahorse males used genes that were conserved throughout evolution and are also used in vertebrates to support pregnancy. But they also brought seahorse specific genes to the placental table. Some of these are elevated during pregnancy, although their exact function is not yet known.

The authors of this recent work on seahorse placentae emphasized “the unique strategy of male pregnancy, that is, the recruitment of both conserved genes and cell types combined with evolutionary species-specific genes and cell types, leading to novel regulatory interactions that gave rise to male viviparity independently in seahorses.”6

I say the natural world is less binary and more quirky than you might imagine.

On the PBS program and in other venues too, I said no. Sex is not binary; there is significant individual variability depending on the roll of the meiotic gene distribution dice, the spinning of the wheel of developmental process, and the roiling of the body/brain as it encounters the shaping influences of complex culture and the material environment. Rather than a biology/fact-based pushback, my opponent rolled her eyes and continued her robotic chant that sex is binary.

As I corresponded with friends in the days after the show aired, I was reminded that, for the most part, people are not privy to the active discussions about non-binary sex taking place right now among biologists, anthropologists, sociologists, philosophers, and health care researchers. And why should they be when they are worrying about the war in Iran, the second rising of Jim Crow, and, literally, the price of gas. So I thought it might be helpful to provide another bibliography as a resource for those who want to push this particular envelope.

There are not a lot of popularly-written books out yet (except see Fuentes, A. (2025). Sex Is a Spectrum: The Biological Limits of the Binary, Princeton University Press) and this list contains mostly academic articles and books, many of which are not easy to find outside of academia, and possibly even harder to read because of the specialized language in which they are written. So I copied the abstracts from each reference listed, and put certain take-home points in bold. I hope this helps anyone who wants to make an evidence-based argument about non-binary sex better understand what types of arguments exist to support the idea of sex as a continuum.

Here are some key quotes:

Beischel (2025) “Taken together, we can see how the science of human sex has accumulated enough evidence of diversity that reducing sex down to two types is misleading at best and harmful at worst.”

Griffiths (2021) “The idea of biological sex is critical for understanding the diversity of life, but ill-suited to the job of determining the social or legal status of human beings as men or women.”

King (2022) “Currently, there are at least 40 known variations that fall into intersex classifications... complex biologic variations can occur in everyone, and sex may best be viewed as a spectrum comprised of many traits.”

McLaughlin et al (2023) “We argue that consideration of “sex” as a constructed category operating at multiple biological levels opens up new avenues for inquiry in our study of biological variation. We apply this framework to three case studies that illustrate the diversity of sex variation, from decoupling sexual phenotypes to the evolutionary and ecological consequences of intrasexual polymorphisms.”

Rehmann-Sutter et al (2023) “Recent data indicate that sex is not a simple binary classification based solely on genitalia at birth or reproductive capacity but encompasses various biological characteristics such as chromosomes, hormones, and secondary sexual characteristics.”

Thinius and Trappes (2024) “Sex is often thought of as a straightforwardly binary categorical variable. Yet there is considerable variation in would-be sex traits; from genitals and hormones to morphology, neurology, and behaviour, there is rarely if ever a categorical binary.”

SO: HERE’S THE LIST

Ainsworth, C. (2015). “Sex redefined.” Nature 518(7539): 288-291.

Arrighi, L. (2025). “The Spectrum of Sex and Gender.” Arch Sex Behav 54(10): 3785-3791.

“Critically, the extensive individual variability makes it extremely difficult and sometimes inaccurate to fit all individuals within either of the three neat and practical categories of male, female, and intersex (King, 2022). For example, most females have two X chromosomes and most males an X and a Y chromosome, but there are around 40 combinations, also defined as intersex conditions or differences in sex development, that diverge from this, and sometimes chromosomes are incomplete or inactivated (Jones, 2018). This can lead to extremely variable presentations across individuals (Carpenter, 2018; Jones, 2018; Moran, 2020).”

Beischel, W. J. (2025). “130 Genders and Counting: On Scientific Fact and Trans Livability.” Arch Sex Behav 54(10): 3797-3802.

“Taken together, we can see how the science of human sex has accumulated enough evidence of diversity that reducing sex down to two types is misleading at best and harmful at worst. These “common sense” understandings of binary sex do not follow scientific understandings of sex and, to the extent that governmental policies should be based in science, should not be the basis for such wide-reaching policy.

Cirulis, A. (2025). “Sex Categories.” Arch Sex Behav 54(10): 3805-3807.

Even though sex, defined by gamete type, is binary, many sex-associated phenotypes show bimodal rather than perfectly dichotomous distributions. In evolutionary biology, it is already common to recognize three reproductive categories when males, females, and hermaphrodites coexist. By analogy, in human biology, medicine, and law, it can be helpful to introduce a third analytical or legal category in cases where there are substantial incongruences between sexrelated traits—for example, in some intersex conditions and in the lived realities of many trans people”

DuBois, L. Z., A. K. Trujillo and M. M. McCarthy, Eds. (2025). Sex and Gender: Toward transforming Scientific Practice. Strüngmann Forum Reports. Cham, Switzerland, Springer.

This book is open access, which means that you have free and unlimited access. It provides an interdisciplinary perspective on the study of sex and gender, emphasizing their entanglement and it suggests directions for future research on sex and gender. https://link.springer.com/book/10.1007/978-3-031-91371-6

DuBois, L. Z. and H. Shattuck-Heidorn (2021). “Challenging the binary: Gender/sex and the bio-logics of normalcy.” Am J Hum Biol: e23623.

“In this article, we discuss biological variation associated with gender/sex and propose ways forward to ensure we are engaging with gender/sex diversity. We base our analysis in the concept of “biological normalcy,” which allows consideration of the relationships between statistical distributions and normative views. We address the problematic reliance on binary categories, the utilization of group means to represent typical biologies, and document ways in which binary norms reinforce stigma and inequality regarding gender/ sex, gender identity, and sexuality.”

Eliot, L. (2025). ““Precision Medicine” and the Failed Search for Binary Brain Sex Differences to Address Gender Behavioral Health Disparities.” American Journal of Human Biology 37(4): e70041.

“Human brain imaging took off in the 1980s and has since flooded the zone in the analysis of gender differences in behavior and mental health. Couched in the aims of “precision medicine,” the vast majority of this research has taken a binary approach, dividing participants according to the M/F box at intake and asserting that the sex differences found in neuroimaging will lead to important advances for treating neuropsychiatric disorders. However, the actual findings from this 40-­year project have not lived up to its promise, in part because of the over-­binarization of sex and general ignorance of gender as a complex variable influencing human behavior and brain function. This paper reviews the history of failed claims about male–female brain difference in the modern era, illuminates the deep-­pocketed incentives driving such research, and examines the limitations of this binary approach for understanding gender-­related behavior and health disparities. It then considers more recent efforts to “break the binary” by using measures of “gender” in addition to “sex” as an independent variable in brain imaging studies. Given the multidimensional nature of gender—as identity, expression, roles and relations—this is challenging to implement, with initial efforts producing little of substance. Better approaches to addressing male–female disparities in brain health will require focusing on specific behaviors (e.g., anxiety, risk-­taking, verbal memory, spatial navigation) and specific components of sex and gender (e.g., body size, hormone levels, gene expression, caregiver role, financial independence, discrimination) when seeking brain-­behavior correlates in a diverse population.”

Eliot, L., A. Ahmed, H. Khan and J. Patel (2021). “Dump the “dimorphism”: Comprehensive synthesis of human brain studies reveals few male-female differences beyond size.” Neurosci Biobehav Rev 125: 667-697.

“With the explosion of neuroimaging, differences between male and female brains have been exhaustively analyzed. Here we synthesize three decades of human MRI and postmortem data, emphasizing meta-analyses and other large studies, which collectively reveal few reliable sex/gender differences and a history of unreplicated claims. Males’ brains are larger than females’ from birth, stabilizing around 11 % in adults. This size difference accounts for other reproducible findings: higher white/gray matter ratio, intra- versus interhemispheric connectivity, and regional cortical and subcortical volumes in males. But when structural and lateralization differences are present independent of size, sex/gender explains only about 1% of total variance. Connectome differences and multivariate sex/gender prediction are largely based on brain size, and perform poorly across diverse populations. Task-based fMRI has especially failed to find reproducible activation differences between men and women in verbal, spatial or emotion processing due to high rates of false discovery. Overall, male/ female brain differences appear trivial and population-specific. The human brain is not “sexually dimorphic.”

Eliot, Lise. It’s a myth that baby boys are less social than girls – a new look at decades of research shows all babies are born to connect Published: April 20, 2026 8:34am EDT https://theconversation.com/its-a-myth-that-baby-boys-are-less-social-than-girls-a-new-look-at-decades-of-research-shows-all-babies-are-born-to-connect-277453 in The Conversation.

Frederick, D. A. (2025). “Gamete Size Is Essential for Understanding Sex and Sexual Selection in Humans, Animals, Plants, and Algae But Configurations of Sex-Linked Traits Are Practically Important for Understanding Sex.” Arch Sex Behav 54(10): 3821-3825.

“I provide some background on why gametes have been central to defining sex across species in evolutionary biological sciences. Understanding this perspective is important because it helps understand the competing frames people are using when they talk of sex as binary instead of as a spectrum or a multidimensional configuration of traits. The gametic central framing is essential for understanding sex and sexual selection across species, whereas the multidimensional configuration framing is practically useful in medical, psychological, and social sciences when studying emergent sex-related structures and how they relate to social roles.”

Griffiths, P. E. (2021). “What are biological sexes.” https://philarchive.org/rec/GRIWAB-2

“Biological sexes (male, female, hermaphrodite) are defined by different gametic strategies for reproduction. Sexes are regions of phenotypic space which implement those gametic reproductive strategies. Individual organisms pass in and out of these regions – sexes - one or more times during their lives. Importantly, sexes are life-history stages rather than applying to organisms over their entire lifespan. This fact has been obscured by concentrating on humans, and ignoring species which regularly change sex, as well as those with non-genetic or facultatively genetic sex determination systems. But the general point applies equally to humans. Assigning sexes to pre-reproductive life history stages involves ‘prospective narration’ – classifying the present in terms of its anticipated future. Assigning sexes to adult stages of non-reproductive castes or non-reproductive individuals is a complex matter whose biological meaning differs from case to case. The chromosomal and phenotypic ‘definitions’ of biological sex that are contested in philosophical discussions of sex are actually operational definitions which track gametic sex more or less effectively in some species or group of species. Neither ‘definition’ can be stated for species in general except by defining them in terms of gametic sex. The gametic definition of sex also features in widely accepted models which explain why two biological sexes – either in separate individuals or combined in hermaphroditic individuals - are almost universal in multicellular species. Finally, the fact that a species has only two biological sexes does not imply that every member of the species is either male, female or hermaphroditic, or that the sex of every individual organism is clear and determinate. The idea of biological sex is critical for understanding the diversity of life, but ill-suited to the job of determining the social or legal status of human beings as men or women.”

Hyde, J. S., R. Bigler, D. Joel, C. Tate and S. M. van Anders (2018). “The future of sex and gender in psychology: five challenges to the gender binary.” American Psychologist.

“The view that humans comprise only two types of beings, women and men, a framework that is sometimes referred to as the “gender binary,” played a profound role in shaping the history of psychological science. In recent years, serious challenges to the gender binary have arisen from both academic research and social activism. This review describes 5 sets of empirical findings, spanning multiple disciplines, that fundamentally undermine the gender binary. These sources of evidence include neuroscience findings that refute sexual dimorphism of the human brain; behavioral neuroendocrinology findings that challenge the notion of genetically fixed, nonoverlapping, sexually dimorphic hormonal systems; psychological findings that highlight the similarities between men and women; psychological research on transgender and nonbinary individuals’ identities and experiences; and developmental research suggesting that the tendency to view gender/sex as a meaningful, binary category is culturally determined and malleable. Costs associated with reliance on the gender binary and recommendations for future research, as well as clinical practice, are outlined.”

King, D. E. (2022). “The Inclusion of Sex and Gender Beyond the Binary in Toxicology.” Front Toxicol 4: 929219.

“Assigned sex is the label given at birth by medical professionals based on an individual’s chromosomes, hormone levels, sex organs, and secondary sex characteristics.. the term “biologic sex” is understood by many to be an outdated term, due to its longstanding history of being used to invalidate the authenticity of trans identities. Although sex is typically misconceptualized as a binary of male (XY) or female (XX), many other chromosomal arrangements, inherent variations in gene expression patterns, and hormone levels exist. Intersex categorizations include variations in chromosomes present, external genitalia, gonads (testes or ovaries), hormone production, hormone responsiveness, and internal reproductive organs. Medical classification of intersex individuals is not always done at birth, as many intersex traits do not become apparent until puberty or later in life. Currently, there are at least 40 known variations that fall into intersex classifications... complex biologic variations can occur in everyone, and sex may best be viewed as a spectrum comprised of many traits.”

Maney, D. L. (2016). “Perils and pitfalls of reporting sex differences.” Philosophical Transactions of the Royal Society of London B: Biological Sciences 371(1688).

“The idea of sex differences in the brain both fascinates and inflames the public. As a result, the communication and public discussion of new findings is particularly vulnerable to logical leaps and pseudoscience. A new US National Institutes of Health policy to consider both sexes in almost all preclinical research will increase the number of reported sex differences and thus the risk that research in this important area will be misinterpreted and misrepresented. In this article, I consider ways in which we might reduce that risk, for example, by (i) employing statistical tests that reveal the extent to which sex explains variation, rather than whether or not the sexes ‘differ’, (ii) properly characterizing the frequency distributions of scores or dependent measures, which nearly always overlap, and (iii) avoiding speculative functional or evolutionary explanations for sex-based variation, which usually invoke logical fallacies and perpetuate sex stereotypes. Ultimately, the factor of sex should be viewed as an imperfect, temporary proxy for yet-unknown factors, such as hormones or sex-linked genes, that explain variation better than sex. As scientists, we should be interested in discovering and understanding the true sources of variation, which will be more informative in the development of clinical treatments.”

Maney, D. L., A. Duchesne and G. Grossi (2025). “Sex/gender entanglement: A problem of knots and buckets.” Biol Sex Differ 16(1): 85.

“When used as variables in biomedical research, sex and gender can be difficult to operationalize and measure. Questions have arisen about whether either category is stable or causally meaningful in a research context. Here, we discuss some of the limitations of using both or even one of these categories in correlational or experimental work. We argue that attempting to draw a distinction between sex and gender can reignite the nature/nurture debate, inadvertently bringing outdated metaphors and assumptions about innateness and causation into our research. Many researchers, including ourselves, have described sex and gender as separate collections of causal factors (which we describe as a “bucket” metaphor) or as entangled (a “knot” metaphor). Because they regard sex and gender as conceptually separable and internally consistent, such metaphors have limited value for understanding the drivers of diversity in our data. Rather than continuing to reify sex and gender as distinct buckets or threads of explanatory variables, we call for deconstruction of these categories by focusing instead on clearly operationalized, instantiating variables that researchers can manipulate or measure. Our proposed approach differs from recent, similar calls in that we are not suggesting the exclusion of a sex/gender category from statistical models; instead, we recommend keeping it—not as a representation of biological reality, but as a tool used under a careful set of assumptions. In addition, we advocate for attention to variation within sex/gender, which is more informative in investigations of mechanism than comparing means across sex/gender categories.”

Massa, M. G., K. Aghi and M. J. Hill (2023). “Deconstructing sex: Strategies for undoing binary thinking in neuroendocrinology and behavior.” Hormones and Behavior 156: 105441.

“The scientific community widely recognizes that “sex” is a complex category composed of multiple physiologies. Yet in practice, basic scientific research often treats “sex” as a single, internally consistent, and often binary variable. This practice occludes important physiological factors and processes, and thus limits the scientific value of our findings. In human-oriented biomedical research, the use of simplistic (and often binary) models of sex ignores the existence of intersex, trans, non-binary, and gender non-conforming people and contributes to a medical paradigm that neglects their needs and interests. More broadly, our collective reliance on these models legitimizes a false paradigm of human biology that undergirds harmful medical practices and anti-trans political movements. Herein, we continue the conversations begun at the SBN 2022 Symposium on Hormones and Trans Health, providing guiding questions to help scientists deconstruct and rethink the use of “sex” across the stages of the scientific method. We offer these as a step toward a scientific paradigm that more accurately recognizes and represents sexed physiologies as multiple, interacting, variable, and unbounded by gendered preconceptions. We hope this paper will serve as a useful resource for scientists who seek a new paradigm for researching and understanding sexed physiologies that improves our science, widens the applicability of our findings, and deters the misuse of our research against marginalized groups.”

McLaughlin, J. F., K. M. Brock, I. Gates, A. Pethkar, M. Piattoni, A. Rossi and S. E. Lipshutz (2023). “Multivariate Models of Animal Sex: Breaking Binaries Leads to a Better Understanding of Ecology and Evolution.” Integrative and Comparative Biology.

““Sex” is often used to describe a suite of phenotypic and genotypic traits of an organism related to reproduction. However, these traits—gamete type, chromosomal inheritance, physiology, morphology, behavior, etc.—are not necessarily coupled, and the rhetorical collapse of variation into a single term elides much of the complexity inherent in sexual phenotypes. We argue that consideration of “sex” as a constructed category operating at multiple biological levels opens up new avenues for inquiry in our study of biological variation. We apply this framework to three case studies that illustrate the diversity of sex variation, from decoupling sexual phenotypes to the evolutionary and ecological consequences of intrasexual polymorphisms. We argue that instead of assuming binary sex in these systems, some may be better categorized as multivariate and nonbinary. Finally, we conduct a meta-analysis of terms used to describe diversity in sexual phenotypes in the scientific literature to highlight how a multivariate model of sex can clarify, rather than cloud, studies of sexual diversity within and across species. We argue that such an expanded framework of “sex” better equips us to understand evolutionary processes, and that as biologists, it is incumbent upon us to push back against misunderstandings of the biology of sexual phenotypes that enact harm on marginalized communities.”

Rehmann-Sutter, C., O. Hiort, U. M. Kramer, L. Malich and M. Spielmann (2023). “Is sex still binary?” Med Genet 35(3): 173-180.

“In this perspective article we discuss the limitations of sex as a binary concept and how it is challenged by medical developments and a better understanding of gender diversity. Recent data indicate that sex is not a simple binary classification based solely on genitalia at birth or reproductive capacity but encompasses various biological characteristics such as chromosomes, hormones, and secondary sexual characteristics. The existence of individuals with differences in sex development (DSD) who do not fit typical male or female categories further demonstrates the complexity of sex. We argue that the belief that sex is strictly binary based on gametes is insufficient, as there are multiple levels of sex beyond reproductivity. We also explore the role of sex in sex determination, gene expression, brain development, and behavioural patterns and emphasize the importance of recognizing sex diversity in personalized medicine, as sex can influence disease presentation, drug response, and treatment effectiveness. Finally, we call for an inter- and transdisciplinary approach to study sex diversity and develop new categories and methodologies that go beyond a binary model.”

Richardson, S. S. (2022). “Sex Contextualism.” Philosophy, Theory, and Practice in Biology 14(0).

“This paper develops the conceptual framework of “sex contextualism” for the study of sex related variables in biomedical research. Sex contextualism offers an alternative to binary sex essentialist approaches to the study of sex as a biological variable. Specifically, sex contextualism recognizes the pluralism and context-specificity of operationalizations of ‘sex’ across experimental laboratory research. In light of recent policy mandates to consider sex as a biological variable, sex contextualism offers constructive guidance to biomedical researchers for attending to sex-related biological variation. As an alternative to and critique of biological binary sex essentialism, sex contextualism contributes to current debates in philosophy of biology, feminist science studies, and social ontology on the construction of categories ofgender/sex differences in scientific research.”

Rippon, G. (2020). A Gendered World Makes a Gendered Brain. Ted Talks. G. Rippon.

Ritz, S. A. and L. Greaves (2022). “Transcending the Male–Female Binary in Biomedical Research: Constellations, Heterogeneity, and Mechanism When Considering Sex and Gender.” International Journal of Environmental Research and Public Health 19(7): 4083.

“Accounting for the influences of sex- and gender-related factors on health is one of the most interesting and important challenges in contemporary health research. In biomedical research, models, experimental designs, and statistical analyses create particular challenges in attempting to incorporate the complex, dynamic, and context-dependent constructs of sex and gender. Here, we offer conceptual elaborations of the constructs of sex and gender and discuss their application in biomedical research, including a more mechanism-oriented and context-driven approach to experimental design integrating sex and gender. We highlight how practices of data visualization, statistical analysis, and rhetoric can be valuable tools in expanding the operationalization of sex and gender biomedical science and reducing reliance on a male–female binary approach.”

Ritz, S. A., G. Bauer, D. M. Christiansen, A. Duchesne, A. K. Trujillo and D. L. Maney (2025). Operationalization, Measurement, and Interpretation of Sex/Gender. Sex and Gender. L. Z. D. e. a. (eds.): 87-112.

“Given the proliferation of calls to consider sex and gender in biomedicine, it is critical to address how the two concepts, and the relationships between them, are being implemented in a research setting. This chapter considers how we might transcend a simple, binary female–male framing and embrace the idea of the entanglement of sex and gender. The ways that the terms sex and gender are typically used in biology and health research are considered, with a focus on the relationships between these constructs, and areas of coherence and disagreement in their conceptualization. Problems arise when sex and gender are principally operationalized in terms of a female–male binary, including not only the resulting exclusion of trans, nonbinary, and intersex individuals but also the inadequacy of a binary analytical framework to account for context, overlap, in-group heterogeneity, continuity, and similarity. Entanglement and interaction are compared and contrasted, three forms of scientific engagement with these ideas are identified, and the implications of intersectionality for the operationalization of sex and gender are considered. In the context of experimentation, an entanglement perspective on sex and gender is explored for what it might enable along with the challenges it presents. As researchers grapple with the incorporation of sex and gender in their work, these frameworks will require ongoing development and refinement, reduced reliance on the dominant binary female–male analytical framing, and a move to a contextual, mechanistic approach that better reflects conceptual complexity, diverse research methods, and intersectional considerations.”

Thinius, A. C. and R. Trappes (2024). “Sex Traits and Individual Differences: Stabilising and Destabilising Binary Categories in Biological Practice.” The British Journal for the Philosophy of Science.

“Sex is often thought of as a straightforwardly binary categorical variable. Yet there is considerable variation in would-be sex traits; from genitals and hormones to morphology, neurology, and behaviour, there is rarely if ever a categorical binary. We introduce a strategy that researchers use to deal with this variation: individualizing variation (IV). IV involves treating non-binary and gradual variation as idiosyncratic, as individual differences rather than sex-based differences. Using the contrasting cases of sex identification in field ornithology and the debate about sex differences in neuroscience, we illustrate IV and investigate its epistemic and conceptual consequences. We argue that IV stabilizes the ontological picture of sex as categorical and binary. While IV can be an epistemically benign research strategy in some cases, we argue that it can also be epistemically detrimental. This is because of its ability to mask evidence that would otherwise challenge related assumptions about the phenomenon of interest, such as what sexes are and what they look like. We also identify an alternative strategy, de-individualizing variation, which works against IV and helps life scientists recognize variation beyond categorical binaries.”

van Anders, S. M. (2022). “Gender/sex/ual diversity and biobehavioral research.” Psychology of Sexual Orientation and Gender Diversity 11(3): 471-487.

“Human biobehavioral research is often rooted in and supports two interrelated binaries: one that divides and essentializes humans into two sexes and values maleness over femaleness, and a second that divides behavior into two sides, assigning more truth to one—nature and sex—over the other—gender, nurture, and culture. As such, biobehavioral research can contribute to the marginalization of gender/sex/ual minorities and policing of people of all gender/sex/ualities. Yet biophenomena are important to psychology and understandings of human behavior. In this article, I lay out how concepts like gender/sex, and methodological approaches like social neuroendocrinology, can help provide a biobehavioral research framework for and from gender/sex/ual diversity. To do so, I go beyond the binaries to define gender, sex, and gender/sex in dynamic and multifaceted ways with aspects that branch and coincide. I delineate the utility of gender/sex, including over sex/gender. I explain how gender/sex and social neuroendocrinology offer biological dynamism, expansiveness/emergence, and contextualism to counter the problematics of biological determinism, reductionism, and essentialism. And, I provide two examples of how gender impacts sex, transforming understandings of each: a pretheory route that constrains biobehavioral research questions and thus understandings of testosterone that circulate in our cultures, and a biomaterial gender?testosterone pathway whereby acute or “chronic gender” modulate levels of testosterone that circulate in our bodies. Throughout, I make clear how this biobehavioral research framework can be a feminist and queer successor science that moves beyond binaries to more empirical, accurate, and just knowledge.”

van Anders, S. M. (2025). “From Testosterone to Racialization to Knobby Knees: 15 Years of Gender/Sex.” Am J Hum Biol 37(6): e70090.

“This paper discusses ~15 years of my research on gender/sex. I first discuss how “sex versus gender” is an overlay onto “nature versus nurture” ideologies, and the ways these are unempirical (if not anti-­empirical), inaccurate, and unjust. I provide definitions of gender/sex, as well as gender and sex, and the pitfalls of “getting sex right” ideologies that aim to provide a singular universal definition of sex that belies its multiplicity, dynamism, and social situatedness. I discuss how these ideologies are often rooted in “bio/logics” that seek to define sex in ways that restrict human rights, especially for gender/sex minorities. I focus on my own research on testosterone (T) beyond masculinity that highlights the importance of gender/sex. This includes thinking about T in terms of social and biomaterial construction, including a “gender → T pathway” and “chronic gender”. I then describe how discussions of T are also rooted in racism, racialization, colonialism, and settler colonialism. In addition, I delineate how this makes not just for “sex versus gender” dichotomies and gender binaries, but ladders or helices that include gender/sex and race/ethnicity, among other social locations. I also point to gender/sex as an important lens for understanding bodily formations beyond T, that include a new “knobby knee hypothesis”. In discussing these topics, I focus on an array of important feminist science principles, including epistemic injustice, pre-­theory, intersectionality, and diffraction. I close by discussing how gender/ sex can provide an avenue for bioscientific research that is more empirical, accurate, and just.”

van Anders, S. M., Z. C. Schudson, E. C. Abed, W. J. Beischel, E. R. Dibble, O. D. Gunther, V. J. Kutchko and E. R. Silver (2017). “Biological Sex, Gender, and Public Policy.” Policy Insights from the Behavioral and Brain Sciences 4(2): 194-201.

“Policy debates have focused on who can participate in or access single-sex activities or services. This article describes how science of the biology of sex is relevant to three major policy areas: parenting (including leaves), sports, and public spaces. We focus on what scientists know about sex and gender (and gender/sex, where gender and sex are intertwined), and the role of various biological factors, including hormones such as testosterone and estradiol as well as genetics, gonads, genitals, and more. The policies under debate often use “biological sex,” but this fails to account for scientific understandings of sex and gender, misrepresents sex as single-faceted and binary, and overlooks scientific consensus about the importance of gender and identity.

van Anders, S. M. and E. J. Son (2025). “Men and Women: Gender Ideology and the Gender Binary.” Archives of Sexual Behavior.

When people ask “Who is a man?” and “Who is a woman?”, they are asking those questions about everyone. They are making judgments and decisions about whether any of us is a woman or man, even for those of us who are cisgender. When people ask “who is a man?” and “who is a woman?”, the very same gender ideologies that are used to justify excluding transgender people from their gender/sex categories also undermine cisgender women and men. In other words, “woman” and “man” are categories with metrics all of us are judged by and frequently found wanting. These gender ideologies are actually neutral or agnostic about people’s transgender or cisgender status and cannot be used to selectively and specifically police transgender people, leaving cisgender people secure. All of us men and women—cisgender and transgender—are only guest visitors on sufferance in manhood or womanhood, so long as we use gender ideologies to police “who is a man” and “who is a woman.””

Velocci, B. (2024). “The history of sex research: Is “sex” a useful category?” Cell 187(6): 1343-1346.

“The history of sex research demonstrates an ongoing coexistence of multiple, conflicting meanings of sex. This history raises questions for scientists about the deployment of a research variable that lacks precision. Cross-disciplinary collaboration between scientists and science and technology studies (STS) scholars offers a way to find solutions to this problem.”

Yang, W. and J. B. Rubin (2024). “Treating sex and gender differences as a continuous variable can improve precision cancer treatments.” Biology of Sex Differences 15(1): 35.

“Some efforts to improve cancer therapy involve the idea of personalizing treatments to who a patient is and how their cancer operates. Personalizing treatment can involve straight forward features like a patient’s age, family cancer history, personal disease and surgical histories, as well as more complex features like analysis of their specific cancer’s mechanisms of growth and spread throughout the body. One glaring omission in common personalization schemes is the sex and gender of the patient. While patient sex and gender is known to substantially affect cancer rates and response to treatment, we do not yet use this information in treatment planning. There are multiple reasons for this but among them is that we tend to think about sex and gender as an either/or categorization. You are either a male/man or a female/woman. This is not accurate as there are many variables that contribute to who an individual is as a male/man or female/woman. This variability is a challenge to incorporating these features into personalized treatment planning. Here, we have developed a method to address this challenge. It is our great hope that this will enable the use of this critically important element of personalization in cancer treatment planning and improve survival rates for all patients.”

Of course she did not take me up on the offer because she doesn’t want to rattle her absolute belief in the binary, which forms the basis for the trans prohibitions. But one of my followers on Bluesky said they would love to have the list. So here it is. Easiest to compile on Substack which does not have a word limit, and share the link on short-form social media.

Trans and intersex history reading list

Compiled 4/19/2026

There is one novel in here, a couple of books on the history of intersex, two on the history of biologists trying to tame the sex category, and one contemporary book on social policy definitions of gender.

• Currah, P. (2022). Sex is as sex does: Governing transgender identity. New York, New York University Press.

• Drescher, Jack and William Byne eds. (2012) Treating transgender children and Adolescents: An interdisciplinary discussion. Routledge

• Eakett, Andrew and Combs, Alex L. (2025) Trans history: A graphic novel. Candlewick Press. (aimed at teens)

• Feinberg, Leslie (1996) Transgender warriors: making history from Joan of Arc to RuPaul. Beacon Press.

• Feinberg, Leslie (1998)Trans liberation: beyond pink or blue. Beacon Press.

• Feinberg, Leslie Stone Butch Blues (1993), a classic novel considered the finest account of the complexities of a transgendered existence, available for free online.( https://www.lesliefeinberg.net/)

• Gill-Peterson, Jules. (2024) A short history of trans misogeny. Verso Books

• Gill-Peterson, J. (2018). Histories of the transgender child. University of Minnesota Press.

• Kates, Gary. (1995) Monsieur D’eon Is a woman: A tale of political intrigue and sexual masquerade. Basic Books.

• Manion, J. (2020). Female husbands: A trans history. Cambridge, England, Cambridge University Press.

• Markowitz, S. (2024). The gender binary and the invention of race. London, Routledge.

• Meyerowitz, Joanne. (2002) How sex changed: a history of transsexuality in the United States. Harvard University Press

• Oosterhuis, Harry (2000) Stepchildren of nature: Krafft-Ebing, psychiatry and the making of sexual identity. University of Chicago Press

• Reay, Barry. Trans America: A counter-history ( 2020) Polity Press.

• Reis, Elizabeth (2021) Bodies in doubt: An American history of intersex. Johns Hopkins University Press

• Richardson, Sarah (2013) Sex itself: The search for male and female in the human genome. University of Chicago Press

See also: https://www.history.com/articles/chevalier-d-eon-french-spy-man-woman

• Skidmore, Emily (2017) True sex: The lives of trans men at the turn of the twentieth century. NYU Press.

• Snorton, C. R. (2017). Black on both sides : a racial history of trans identity. University of MInnesota Press.

• Stryker, S. and S. Whittle, Eds. (2006). The transgender studies reader. New York, Routledge.

• Stryker, Susan. Transgender history: The roots of today’s revolution. 3rd ed., Seal Press, 2026.

• Valentine, David (2007) Imagining transgender: an ethnography of a category. Duke University Press

• Velocci, Beans. Sex isn′t real: The invention of an incoherent binary. Duke University Press, 2026.

As we witness, in this moment, a form of masculinity that is so toxic that it has put us on the verge of a third world war, an analysis of toxic masculinity seems more than a little apt. So first the basic question: what is it? Is it a social structure? An individual personality trait? Are there many types of masculinity? If so who has what form and why? First, a personal disclaimer. There are many men in my life; they are interesting, warm, funny, kind, and, well, definitely not toxic. I love them and support them in their diverse versions of masculinity, and I have channeled one or another of them non-stop as I worked on this essay.

So if not the men I love, then who? During the 1980s the concept of toxic masculinity developed within a loosely organized men’s movement devoted to assessing the effects of gender/sex roles on men’s psychological development. Movement members posited that when an individual equated his masculinity with emotional suppression, aggression to the point of violence, and a profound fear of femininity in men, the results could be ugly.1 I still shudder as I remember a December afternoon in 1989 when an armed intruder burst into a mechanical engineering class at the École Polytechnique in Quebec, Canada. He told the men to leave, said that he was “fighting feminism”, and then shot the remaining nine women. He continued shooting as he moved through the school, targeting women and then shooting himself. Fourteen women, mostly science students in their early 20s, died.2 It was frightening. I had become known for advocating for women in science and I could not understand why pushing to make science more diverse evoked such violence.

Pretty disturbing, right? But men in general can’t be held responsible for a one-off shooting or the more common wife beatings. (I was also on the board of a Rhode Island shelter3 for victims of domestic assault—the location of which was secret to protect the women and children within—so this too was on my mind.) Were these examples of a real syndrome—toxic masculinity—or was the phrase just a catchy meme? I thought I knew it when I saw it, but hardly anyone has seriously investigated toxic masculinity as an individual personality trait. So I was fascinated, now, over thirty years later to read the results of a study appearing in The Psychology of Men and Masculinities (published under the auspices of the American Psychological Association). The article title: “Are Men Toxic? A Person-Centered Investigation Into the Prevalence of Different Types of Masculinity in a Large Sample of New Zealand Men”. 4

Hoping to improve the tone and methods of past work, the study’s authors, led by the psychologist Deborah Hill Cone, analyzed data from a large New Zealand survey of Attitudes and Values, done from 2018-2019. They focused on results from 15,808 heterosexual men, ranging in age from 18 to 99 years, and from diverse ethnic (although 80% white) and economic backgrounds. After scouring previous studies for items that might be associated with toxicity, they chose 8 constructs to measure. I have organized these in Table 1.

Table 1: Constructs used to investigate patterns of masculinity

In the end they had over 15,000 answers to these 8 fairly complex constructs. To make sense of this mass of numbers, the researchers used a type of analysis called latent profile analysis. They wanted to extract groups with common response patterns from the answers to the 8 constructs, and they managed to distill out five profiles which they labeled —hostile toxic, benevolent toxic, anti-LGBT moderate, LGBT-tolerant, and atoxic. (I would love to hear from statisticians about how solid their statistical methods were, as I am unfamiliar with latent profile analysis).

I reproduce their graphic summary here, and pull out a few highlights. First, more than 60% of the men had an atoxic or LGBT tolerant Moderate profile. All of the men had fairly similar scores on gender identity centrality, and the tolerant and atoxic groups were also low in sexual prejudice, narcissism,and domestic violence prevention. Two profiles, summing up 11.5% of the men were labeled toxic (hostile or benevolent). Both scored high in sexual prejudice, while the hostile group also scored high on hostile sexism, opposition to domestic violence prevention, and social dominance orientation.

The psychologists and sociologists who authored this study also found that atoxic men were more likely to be employed, be in a relationship, and have had more education than hostilely toxic ones. Hostile toxicity was greater for those who were religious.

The scientists concluded: “the odds of belonging in the Hostile Toxic profile relative to the other profiles tended to be higher for men who were older, unemployed, single, religious, and an ethnic minority, as well as those high on conservatism, deprivation, and emotional dysregulation. In contrast, both education and body satisfaction decreased the odds of belonging in the Hostile Toxic (vs. Atoxic) profile.”

Deborah Hill Cone and her colleages agreed “that most men are not “toxic””, but there was that ~11% of the sample who had profiles they thought of as worrisome. While highlighting “the diversity of masculine identities,” they also believed that their study offered a baseline “ for developing a comprehensive understanding of how toxic indicators may (or may not) be related to masculinity.”

Interesting. But the article left me a bit mystified. The title “Are men toxic?” was equal parts catchy and misleading. The article didn’t really address whether men are toxic. Instead (and I’m not knocking this) it identified patterns of beliefs and personality traits within a large population of men. Their finding, that there is more than one way to be masculine seems unsurprising. To what extent, though, are these masculinity patterns associated with specific behaviors—the ones that lead to murdering female science students or brutalizing domestic partners or children? Are the men they have identified as Hostile Toxic more prone to violent behavior, especially directed at women, than the benevolent Toxic or anti LGBT moderate groups? And I can’t help but wonder where the Epstein class of super-rich, privileged, elite men would fit in the identified profiles. The authors suggest these men may be anomalous and that most toxic attitudes lie with underprivileged men . Here’s how they put it:

“Thus, high-status men who espouse toxic views, such as misogynist influencer Andrew Tate, are not representative of most men with toxic views. These findings also corroborate the broader body of crosscultural work showing that toxic attitudes tend to emerge among the least advantaged groups and are consistent with the resurgence of support for U.S. President Donald Trump among working-class ethnic minority men . Future work is required to investigate whether high-status individuals are capitalizing on (or fomenting) toxicity among these—and other—deprived populations.”

Something is missing in this analysis. They really trust their data, which is a good thing, I guess. But they aren’t worried enough, IMHO, about anti-working class bias or stereotypes. Calling the ribbed cotton tank tops that my father used to wear “wife-beaters” comes to mind as an influential classist meme about men who buy 10 packs of cotton undershirts. Or maybe they needed a different construct to capture how power and wealth can promote toxicity.

Is toxic masculinity a real thing? Confronted with men, such as our current Secretary of Defense, who play act a definition of being “a real man” that combines hyperaggression with profound sexism, racism, and homo and trans phobia, and videos of blowing stuff up, the answer is yes. But doesn’t this person embody an ideology rather than a personality trait?

Is toxic masculinity a useful construct for understanding why some men behave violently toward women? In recent years feminist scientists have called on researchers to stop using the words sex and gender as stand-ins for undefined underlying features. Consider the often published statistics that women have higher rates of immune disease than men. Most often that’s as far as it goes. Scientists simply state that this is a known sex difference with the unspoken causal assumption being that men and women differ biologically. But feminist scientists have pointed out that there are other possible routes to such a difference. Are boys and girls, and later men and women, differently exposed to dirt and microbes, because of their different gender roles? Might this affect their microbiome? Further, might different exposures relate to gendered norms of play for children?5 Wouldn’t our understanding of violent men be aided by analogous reasoning, by looking beneath a glib label at factors that lead to violence and hostility?

Recently two feminist bio-scientists noted that the idea of sex as an important participant in studies of human development and behavior is used in several different ways.6 Most often scientists use sex categories to divide study subjects into two buckets—male or female. By analogy this seems to be the gist of this study on masculinity—creating categories of masculinity. But sex, they wrote can also be understood as a dynamic system, with numerous interacting features promoting the emergence of a variety of attitudes and behaviors. Deborah Hill Cone and her colleagues identified certain important components or correlates of the categories they teased out of their data; they have given us likely components of masculinity as a dynamic system. Next, we need to learn more about how the properties of masculinity, the nurturing, the caring, the achieving and creative, and, sadly, yes, the hostile and violent emerge from this developmental dynamism. Toxic masculinity is not—analytically speaking—a helpful concept. Masculinity as a dynamic system is.

My colleagues Dr. Lisa Diamond and Scout wrote as my guests in a November 24 post: Don’t let this moment be erased. Tomorrow it will be one year since you-know-who took office. He wasted no time attacking the LGBTQI+ community in too many ways to enumerate here. Social science researchers Diamond and Scout understood that when the NIH and NSF killed research on the LGBTQI+ population, an easy answer to the question—to what effect?— would be hard to get. So they designed a survey to check in on our (and your) well being. It is easy to take (I took it and learned a bit about myself in the process). The more data they collect, the greater strength the results will have when we look to repair the damage. (And we will look).

At any rate, the survey will close soon, so I urge everyone, and everyone’s friends, family (it is open to family and allies), new acquaintances, work buddies, classmates—you get the idea, to take a minute to fill it. If you need a little kick to do it, take a look a some of their preliminary findings.

In other words, the cuts to jobs and health care, the burying of LGBTQI+ concerns, the demonizing, the unchecked spewing of hateful words, and yes, in our faces right now, the murder of a lesbian mom who was peacefully defending her community, all this matters. It has hurt our community and those around us. And it has also hurt other minoritized communities—immigrants, African Americans, other Americans who do not look like Nordic Gods. Documenting the effects of Year 1 of the Tr@#&mp regime with the Community’s survey is a critical step for addressing the now and fixing the future. Take the survey!

Part II

Writing Part I dredged up a couple of asides, things I’ve been wanting to say during the past year.

Aside # 1: Collecting community data in is not a new thing. It has been an important go to in the African American and feminist communities. Consider W.E.B. Dubois book The Philadelpia Negro. Dubois and pioneering sociologist and suffragist Isabel Eaton conducted a door-to-door survey in Phillys 7th Ward. (Eaton appended a “Special Report on Domestic Service” to the main book1). In the end they interviewed more than 5000 people, using a survey that “entailed questions about occupations, health, education, and religious, social, and family life.”2 They concluded that the problems faced by African Americans in 1888 Philadelphia arose from job discrimination, rent-gouging, and the lingering effects of slavery, not from some inherent biological difference between blacks and whites.

In the same era, feminist and one of the first women to practice medicine in the United States, Mary Putnam Jacobi answered a screed written by Dr. Edwin Clarke in which he argued that women could not tolerate the rigors of higher education because their each month menstruation disabled them. Jacobi’s 1876 essay “"The Question of Rest for Women during Menstruation," won the Boylston Prize at Harvard University.” In it she gathered “statistics, and sphygmographic tracings of pulse rate, force, and variations to illustrate the stability of a woman's health, strength, and agility throughout her monthly cycle”.3

Aside # 2: It is not new that communities and talented individuals have taken data collection into their own hands. Nor is the attempt to destroy knowledge so that there is no there there against which to fight back. In fact during the second half of the 20th century (and not counting the Third Reich) it became so common, that scholars in the field of Science and Technology Studies gave it a name. It is not a word that trips off the tongue, or immediately enlightens someone unfamiliar with the practice of making information disappear. But it is the word we have—agnatology—and there is scholarship to explain it. The historian Robert Proctor coined the word from the Greek agnosis (non knowing) and “ology” (the study of) when he studied the tobacco industry’s efforts to hide the lethal effects of smoking. He and feminist historian Londa Schiebinger, edited the founding book on the study of ignorance. Agnotology: The Making and Unmaking of Ignorance (2008), contained articles on an impressive number of topics, from climate change to orgasm.

So we are seeing the process again. From Robert Kennedy’s shenanigans at the CDC to the removal from government websites of data on LGBTGI+ lives, to the cancelling of grants to study the health and well-being of minoritized populations in America, we see agnosis at work. If we have no data, we can’t define a problem. No problem? Well, nothing to fix here. So OUT : The Community Survey, responds to a regressive tactic that, itself, has a long history. And the designers of and the participants in the survey are part of a long and impressive history of pushback, from Mary Putnam Jacobi and W.E.B. DuBois, to today’s agnatology scholars . It may not require a loud whistle or a frog suit, but filling out the survey is definitely an act of resistance.

Since Donald Trump has taken office and taken aim at diversity and equity research, and at science that concerns the health and welfare status of the LGBTQIA+ community, grant after grant has been canceled (see https://grant-witness.us/ ) and painstakingly accumulated research databases (https://www.statnews.com/2025/01/31/cdc-removes-data-on-sexual-orientation-gender-identity-from-website/) have been deleted from government websites. The lesson of erasure is the same one I learned at Brown —if there are no data, there is no problem. But if you have the receipts then something must be done.

Now I am proud to facilitate the announcement of a new effort to keep the data coming. LGBTQ scientists are taking measures, and I am happy to host the announcement of one grass roots effort to keep collecting data, federal grants be damned. Scientists Lisa Diamond and Scout want to hear from you. Here they are, in their own words. Please take their survey and spread the word as far and wide as possible.

--Anne Fausto Sterling, November 22, 2025

DON’T LET THIS MOMENT BE ERASED

By Lisa M. Diamond, Ph.D. University of Utah

Scout, Ph.D., The Cancer Network

Everyone connected to the LGBTQIA+ community – including their loved ones and those who work with LGBTQIA+ communities – has been affected by what has happened this terrible year. But because of the defunding of LGBTQIA+ health research and the elimination of sexual/gender identity questions from federal health surveys, our ability to TRACK what is happening has been cut off at the knees.

We can’t let this happen. So some of us have joined forces to launch a completely unfunded, all-volunteer, hand-to-hand effort to measure the specific mental and physical health effects of the past year, on everyone connected to LGBTQIA+ communities.

We’re asking you to take this short, 25 min survey, share it with your family and friends (our IRB approval includes YOUTH!), and share it with your colleagues. It’s open to LGBTQIA+ folks, their loved ones, and anyone whose work involves these communities. And it’s open to YOUTH as well as adults.

OUT COMMUNITY SURVEY

We have partnered with a variety of state and national organizations to GIVE them the findings for their local communities by February 1, so they can use these data in their 2026 advocacy. By taking this survey, you are helping to represent the needs of your OWN local community.

A unique aspect of the survey is its inclusion of “the workforce” – health care providers, therapists, advocates, teachers, researchers, day care providers, social workers, etc -- anyone whose life intersects with the LGBTQIA+ community. We want to show the full scope of the impact. If you have connections to professional organizations that serve the LGBTQIA+ community, PLEASE SHARE THIS WITH THEM!!!

Here’s a downloadable FLYER with a QR code for posting, sharing on social media, etc.

We’re doing everything we can to get the word out, but it’s hard without funding. If you’d like to help us purchase ads to boost our reach, click the link below to donate funds for this purpose (the National LGBTQIA+ Cancer Network is hosting this effort, and they are a nonprofit, so any donations are tax-deductable). DONATE TODAY

But most important, TAKE THE SURVEY YOURSELF and pass it on.

If you’d like more background on why we’re doing this, and why this moment is so critical, here’s a recent podcast interview where we discuss the study, and why it’s so important to make sure this moment in history does not get erased.

In love and solidarity,

Lisa M. Diamond, Ph.D. University of Utah

Scout, Ph.D., The Cancer Network

Emotionally, it makes sense to me that the grumpy Grinch would envy the humble plant. These green ones do not need to hunt or raise farm animals in order to grow and reproduce. And from envy to thievery is a simple step. We may not know, intuitively, why the Grinch stole Christmas, but stealing a plant’s generating stations and using them for his own nutrition seems like a no brainer!

I realized all of the above upon reading a new article with the ponderous title “A host organelle integrates stolen chloroplasts for animal photosynthesis”, published recently in the biology journal Cell.1 It has been decades since the extraordinary scientist, Lynn Margulis (1938-2011) proposed that complex animal and plant cells evolved when one primitive cell ate another. Sometimes one of the eaten organisms settled into its new environment and made a molecule that promoted its predator’s survival. In time it adapted to its interiorized life style, lost its ability to survive independently and became a component of its host cell. Many doubted Margulis at first, but, both brilliant and tenacious, in the end she won the day.2 Now biologists commonly accept that mitochondria—the so-called cellular energy factories— and chloroplasts—the organelles that capture energy from the sun and turn it into sugars that fuel plant cell growth and development—as well as several other organelle, once were free-living organisms that became symbionts, living inside and in support of a larger cell.

Plants are green because their cells have chloroplasts which use chlorophyll a green-colored molecule, to snag energy from the sun. Animals are not green because they don’t have chloroplasts. Animals have to move around, looking for food, They eat, they rest, they move again. It can be truly tiring. So wouldn’t it be great if an animal could eat some plants and keep the chloropasts, just like those original single-celled organisms did when they first acquired mitochondria and chloroplasts? The Cell research paper tells us how the sea slug, Elysia crispata, has pulled off just such a hijack. Margulis would, I feel confident speculating, have loved this article.

Here is a rough sketch of what this international team, that included scientists from Harvard, the Scripps Oceanographic Institute, the University of Gronigen (Netherlands) and the Dana Farber Cancer Institute, found. Picture the slug scraping green algae off of the surfaces of rocks and shells. As it scrapes, it punctures the algal cell wall, the cell membrane breaks, and cell parts such as the chloroplasts travel into the slug’s gut. There, specialized gut cells ingest free-floating chloroplasts using a process (shown in Figure 1) called phagocytosis. Usually the membrane surrounding the ingested food particle lets in digestive enzymes that break down the food and allows the cell to absorb it. What makes a kleptosome a kleptosome, the authors hypothesize, is that the membrane it uses to surround the engulfed chloroplast excludes the digestive juices, and, through an array of ion pumps and specialized molecular transporters, makes an interior environment that supports the chloroplast. Happy in its new environment inside the gut of the sea slug, the chloroplasts photosynthesize and supply the sea slug with welcomed nutrients.

Until, that is, the sea slug hits hard times. Much like leaves in August (in the Northeastern United States) if sea slugs starve for several weeks they turn orange. Under starvation conditions, apparently, the kleptosomes stop supporting chloroplast happiness and let in the digestive enzymes. These break down the green chlorophyll revealing orange carotenoids—pigments probably also contributed by the original algal meal. In the good times the chloroplasts supplemented the slug’s nutrition. In the bad times, the chloroplasts became just another edible vegetable.

With this last twist, the sea slug’s path diverges from the Grinch’s. According to Chat GPT, an admittedly fallible source, once having become green, the Grinch never turns orange. (See Figure 2) One wonders, though, what might happen if the Grinch lost access to its food stamps.

Link to Throwing Like a Girl

Plain english summary

“The belief that boys and girls throw differently is widespread. The scientific findings supporting this belief, while numerous, vary greatly in terms of method and the age of the children studied. Furthermore, research projects are usually based on a two-fold binary paradigm: first that the important contrasts are between boys and girls; second that studies of variation in throwing form illuminate the degree to which nature compared to nurture contribute to reported differences. Here, I present an alternate paradigm—the analysis of motor skills as they first develop during infancy. This paradigm embraces nurture/nature and gender/sex as entangled and best understood as a dynamic whole; it also allows us to understand throwing form and skill as a continuum or spectrum rather than a binary construct. To offer a concrete instance, I describe the ball-playing activities of 10 infants aged 6–15 months and their mothers. The five boys all began to play active ball games with their mothers at the average age of 9.7 months. This early playing happened before they could walk, and they mastered stable two-handed overhead throwing from a sitting position. The girls and their mothers did not play ball until the babies averaged 12.1 months. Four out of five of the girls were learning to walk and throw at the same time, a condition of instability that made it difficult for them to fully raise the ball above their head without falling. We hypothesize that differences in timing and frequency of play events lead to continuous variability in the embodiment of throwing skills.”

Final Provocation

“Here is my final provocation. If someone does NOT throw like a girl, does that mean they throw like a boy? Are throwing style and throwing force binary? I sincerely doubt it. If, as I urge in this paper, we follow development using longitudinal, naturalistic, qualitative observations, I suspect we will uncover a great deal of individual variation. Children will vary in the timing and method by which they acquire increasingly complex motor skills. Households and dyads will vary in the frequency with which ball play is an important feature of early development. And we will encounter training and feedback offered by peers and older siblings. If what truly exists is—dare I say it—a spectrum of throwing styles--we can, certainly, continue to use standard statistics to create binary gender/sex bins [78]. In doing so, however, we will lose insight into how motor skills develop in babies and how they are promoted and refined as children grow to adulthood. Instead, I urge using qualitative longitudinal, naturalistic observations to help frame specific questions aimed at investigating individual variation rather than aggregate group differences.”

Questions? I am happy to respond to genuine inquiry. I feel free to ignore trolling.

I want to focus on the Rubella virus, otherwise known as the German Measels. When I was a child it was a disease that people hoped girl children caught, not out of malice towards girl children, but because getting it provided life-long protection against future infection. That was and is important if that girl child grew up and became pregnant. Because getting a Rubella infection in the first third of pregnancy is a guaranteed disaster. During that time offshoots of the central neural tube—the eyes and ears—develop, as does the heart. Here’s what the timing looks like (Figure 1).

In weeks 4-6 after sperm-egg fusion the embryonic heart, eye, and ear are taking major shape. Later on they continue to develop, filling the details into the broad outline hammered out in the embryo. Insults that disrupt cells during that early period will likely disrupt anything that is actively forming. In this example Rubella is that insult. The embryo supported by a person who contracts Rubella in the first trimester of pregnancy stands a good chance of suffering from Congenital Rubella Syndrome (CRS). During the first 11 weeks this means heart defects, impaired hearing and congenital cataracts. During this time period, 90% of embryos carried by infected carriers will be affected. The data in Figure 2 provide good reasons to want to have been immunized—either through having caught the disease or via vaccine—well before any chance of pregnancy.

Now picture this: a significant number of children never get vaccinated and don’t catch German measles in childhood. As adults, some of them become pregnant, and one of their kids brings the virus home from school. The result: loss of the pregnancy or the birth of a severely damaged baby. The reader can see that I am not being overly dramatic by considering some fairly recent history. (By recent, I mean it happened in my lifetime)

According to the CDC the last major Rubella epidemic (1964-1965) infected over 12 million people. The results: over 11,000 fetuses lost, 2100 newborn deaths, and 20,000 babies born with severe birth defects such as blindness, deafness, and heart anomalies. This, I’m afraid, is where those who oppose abortion because they “love life”, but also object to requiring school children to have been vaccinated against Rubella, lose me. It is quite predictable that NOT vaccinating school children will sooner or later fuel an epidemic that will result in the death of tens of thousands of fetuses and newborns, and the birth of even more who suffer from profound disabilities. How is this loving life?

This scenario is not a guess. We know that public health measures have saved lives. Mass vaccination is pro-life. The receipts that back this statement are in Figure 3 1.

So all you pro-lifers out there, is this what you want? The new anti-vaccination fad, if successful, will mean that a pregnant woman may contract Rubella, and her embryo, fetus, or newborn may die because a group of politicians—with your support— has managed to smash apart a functioning public health system that protected unborn embryos for real.

The story for this post is about the complexities of sex determination. The Trump Executive Order on Sex and Gender (see prior substacks https://sterlinga.substack.com/publish/posts/published esp WTF 1-3) claimed that biology is simple: males are beings with small reproductive cells, females are beings with large ones. No complexity here. No ambiguity. And certainly no diversity. Either an individual is a male or female. BOOM! That’s it. Biology has spoken.

Source: http://bionalogy.com/pre-implantation_development.htm 50 micrometer cell is the sperm, 150 micrometer cell is the oocyte

Everyone starts out as a single cell—the fertilized egg. Only as the one cell divides into many do the resultant multitudes take on different shapes and functions. They become muscle, bone, nerve, blood, and also big or small reproductive cells. How does that happen? Before fertilization, a human sperm (the little one) usually carries 22 autosomes (not “sex” chromosomes) and either an X chromosome or a Y chromosome. The oocyte (the big one) also usually carries 22 autosomes, and also usually an X or only very rarely a Y chromosome. So when big and little fuse they form a single cell that has 44 autosomes and two XXs or 44 autosomes and an X and a Y chromosome.

But first the sperm has to reach the oocyte. To become svelte enough to make the journey from the vagina, past the cervix, across the vast uterine space, and into the oviduct (where it encounters the big cell), it forms (in the adult sperm-producing person) into a motile, compact cell. To package its considerable volume of DNA into a streamlined nucleus, the forming sperm uses special proteins, called histones, to compact its DNA into almost crystalline form.

As a solution for storage and transport that works well. But once the sperm nucleus finds itself inside the ovum, it has to start doing its part—using its genes to make RNAs. These in turn guide the synthesis of proteins that, together with the big cell’s gene products, guide early development. Here’s where the story I want to tell begins. The sperm DNA has to de-crystallize. It has to unwind, hang more loosely, make space for other molecules—enzymes and messenger RNA’s (RFK not withstanding1) for example—to lock onto specific gene sequences and get the embryo up and running. This means getting some of those histone packing proteins out of the way.

One gene in particular, called Sry (for Sex-determining Region Y gene), becomes active in particular cells of the embryonic gonad just as development of a single, bipotential gonad choose ones of two paths—forming either a testis or an ovary. Previously, a group of researchers in Japan and Australia showed that an enzyme named KDM3A changes the shape of one of the histone proteins that package the SRY gene for transport.2 In doing so it opens it up so that it can regulate the transcription of a suite of genes that direct testis development.

This summer, in the June 2, 2025 issue of Nature, these same scientists presented a related and until now unsuspected finding (using mice as their model system): to act as an enzyme in the embryonic gonad, KDM3A needs the ionic form of iron (Fe2+=ferrous ion with two positive charges). Did basic iron metabolism, they wondered, play a role in sex determination? Maybe the spinach eating Popeye was onto something!

As scientists are wont to do, they approached the matter systemmatically. First they looked to see if Fe2+ was even present in the embryonic cells responsible for sex determination. And sure enough, the ferrous ion accumulated in the critical cells. Looking further, they reported that the genes that code for KDM3A, and that influence iron accumulation, are expressed at higher levels in cells concerned with male sex determination at the time that bipotentiality transitions to two possible developmental pathways.

Definitely suspicious. But could they firm up a link between iron metabolism, the opening up of the Sry gene, and male sex determination? To push this angle, they focused on a gene needed to transfer iron into cells. Mutations in this gene are actually lethal if present in every cell in the body. The mice survive, though, if researchers selectively interfere with the gene in some cells but not others. In this case the scientists disrupted the iron transport gene only in cells concerned with gonad formation. After running a swath of controls they reported that they had succeeded in lowering the levels of iron in the cells, and that cells with lower iron had reduced Sry gene expression. More tests made it likely that Sry expression was reduced because, without the right levels of Fe2+, the critical region of DNA could not properly unwrap from the form it has assumed when it packed into the traveling sperm head.

O.K. Cool. But THEN what happened?

Well next, they cultured prospective embryonic gonad tissue outside of the embryo (tissue culture—in vitro). With time in culture the XY tissue signaled testis differentiation by testing positive for a protein (SOX9) important to testis differentiation. XX tissue signaled differentiation into ovarian tissue by testing positive for FOXL2, a protein essential for ovarian development. Next, they treated the undifferentiated bipotential tissue with a chemical that knocks Fe2++ ions out of commission. The result: in untreated XY gonads no ovarian tissue (FOXL2+) differentiated, but when they sucked the iron out of circulation, almost 90% of the XY gonads developed ovarian tissue!

So far, so good, but are these in vitro findings relevant to an actual pregnancy? To produce an iron-deficient pregnancy they gave an iron vacuuming agent to pregnant mice and then looked at the embryos as they developed in the uterus (in vivo). They examined 72 XY mice born to iron deficient mothers. Four had 2 ovaries and one an ovary and a testis. As a last experiment they fed mice an iron-deficient diet, from several weeks before pregnancy through the first two weeks of pregnancy. This treatment interfered with Sry function and in some cases induced the developing gonad in an XY embryo to form an ovary instead.

This is a lot of fascinating science; so let me emphasize three points that caught my attention.

(1) In the beginning, gonads are bipotential. Whether an embryo is XX or XY, it starts with a single gonad that can, potentially, become either an ovary or a testis. Which direction it takes depends on the tissues developing around it and on which genes become active at the right time and in the right sequence. This basic principle has been known for a long time, but the article discussed here provides a precise example.

(2) A nucleus is not a nucleus is not a nucleus (DNA is not DNA is not DNA). To explain how iron promotes testis development in XY embryos, I had to explain that making a motile and compact cell (the sperm) involves packing the DNA in the nucleus up tight. But packing it also makes it non-functional. Once the sperm and egg cells fuse, however, and the chromosomes comingle, a new nucleus—that of the embryo—forms. At this point the job of the DNA that the sperm contributed is not to grope its way up the female reproductive tract; it is to actively participate in building the embryo. For that, the DNA has to unpack, and ferrous ions turn out to be important for this process.

(3) Finally, embryos develop in an environment that reaches well beyond the womb—to what the mother eats (iron-containing foods, for example), how stressed she is or whether she gets sick because she has not been vaccinated against a virus (Rubella, for example) known to damage the hearing, vision and heart of the developing embryo. People who really care about the safety of the embryo before birth might best spend their efforts supporting research on basic science, such as discussed in this essay, and public health measures that provide pregnant people with proper nutrition.

So enjoy the basic science, have some spinach, and remember that even mice can provide a useful basis for sound public policy.

There are two commentaries accompanying the study, one by me and one by Christia Spears Brown. It also looks as if the monograph authors will be supplying power point and teaching and research resources for the material in their Monograph. Congratulations to the authors. I urge everyone to read the whole thing, statistics, tables and all. I know the techicalities will be hard for some, but ask us all for help and we can try to explain in these pages.

Here is a link to the Monograph online. Download the PDF. It’s important.

But I have talked myself back into it. Science discoveries ARE fun, to be sure. But who’s to say we don’t all need to experience some moments of pleasure and wonderment. Also, part of the battle we are waging is about knowledge. Why is it under attack? Can remembering its pleasures help defend it? When I started this substack I intended to intersperse snippets about new science and about the social nature of scientific knowledge with commentary about the contemporary flashpoints of gender/sex and race. So, I have told myself, it is OK to report on several new articles about life in the hadal zone, far below the ocean’s surface.

Ocean trenches such as the Mariana are deep. The hadal zone of the Pacific Ocean Mariana Trench, which the papers I will cite explored with both robotic and human-occupied submarines, is 4 to 7 miles down. Life there exists in total darkness, under immense pressure and ice-cold temperatures. Before 2020 only nine people had reached the trench’s deepest point, and even now, with improved engineering, not many have descended into the depths. But recently, in the prestigious journal Cell, a team based in Shanghai, China reported the details of explorations that started in 2021.1

Amazingly, organismal diversity abounds in this profoundly inhospitable environment. During 32 dives, Chinese scientists descended into several deep ocean trenches in a research vehicle that collected 1,648 sediment samples from the ocean floor. Back in Shanghai, they extracted and analyzed DNA from the sediments, and found “7,564 microbial species (89.4% unreported).”2 The researchers identified two general molecular strategies these organisms used to evolve such surprising diversity—streamlining and versatility.

As some groups hunkered deep down, they streamlined their metabolism. Their genomes became smaller and their genes more focused on a limited number of metabolic options. Think about it in terms of pasta, which, for the sake of my metaphor, floated in deep ocean currents. First, species that had lived way up top, on a varied diet, ventured into the deep. Some of these managed to reproduce in the deep by digesting spaghetti. Next, some spaghetti eaters became even more specialized—metabolizing only the existing unattached ends, while others evolved the ability to snip a strand in the middle, producing two new ends, and so on. Some species learned to eat other pasta, say, rotini, but only from the inside out, while others stuck to the outside and digested their way inward. As they specialized, they simplified cell maintenance and reproduction by jettisoning genes that had no function in pasta digestion. In contrast, some microbial groups embraced versatility. They had relatively larger, more general purpose genomes and they could eat pasta (again this is a metaphor) in a variety of formats. There were fewer versatiles and they were found in more shallow parts of the hadal, suggesting that adapting to the deepest and harshest environments required the greatest specialization. We can see why that might be so if we move on from microbes, to look next at some of the small but multicellar creatures living in the deep ocean.

The deep hosts more than single cell microbes. Amphipods, small, multicellular crustaceans found in both fresh and salt water, also abound. And they draw their strength from symbiotic relationships with certain gut microbes.

Up at the surface, phytoplankton are busy photosynthesizing, growing, dividing to make new cells and, of course, dying. Their little bodies gradually sink to the bottom where the long organic molecules they have made by removing carbon from the atmosphere become food for the deep-dwelling amphipods, which, in this way, rely on plants and photosynthesis, much as humans do when they eat meat from a cow that grew up eating grass. Microbes living in the amphipod’s gut partake of the food scavenged by the amphipod as it forages along the bottom.

In return, the microbes apparently offer up protection against the intense hydrostatic pressure. They probably do this in several ways, but here’s one: a small molecule called trimethylamine N-oxide (TMAO), known to mitigate the effects of low temperatures and high pressure.3 Hadal microbes make and use TMAO to protect themselves from their super-hostile environment. Even better, one of the microbe species found in the amphipod gut has a mutation that prevents the breakdown of TMAO, meaning it can accumulate enough for itself and pass on the leftovers to its host. In other words, in exchange for being fed when the amphipod grazes on the sunken remains of surface level phytoplankton, gut microbes make enough TMAO to protect itself and the little water shrimp from being paralyzed by the cold or implodng from the water pressure. Bennies all around.

One last, sobering note, though. Human hands reach deep. Seven miles down the research team encountered beer bottles, soda cans, plastic bags and, amazingly, a plastic laundry basket. But ever hopeful, the Chinese research team emphasized the possibility that deep sea organisms, desparate for any sort of food, may yet evolve new ways to eat plastic and other organic pollutants. Perhaps we surface dwellers can use this potential microbial invention to finally clean up the mess we made. We can only hope!

Pressure management

This has been in the works for while, people. I just re-read an essay I wrote 21 years ago. At the time Bush II and his Republican allies had not graduated to using a car crusher. A sledge-hammer worked well enough to soften up the target. And the science establishment, which believed too strongly in its own inevitability, and was too arrogant to imagine how things might go 20+ years into the future, figured it could get by. Give in a little on a museum exhibit, continue to play footsie with big business interests, and look the other way as the right wing softened them up for the knock-out punch. Below I reproduce how it looked to me in 2004. It was not so different then, except that at the time it was a punch in the ribs. Now it is a knock-out blow.

First, the books on gender/sex diversity in the non-human biological world keep pouring in. In this post I’ll alert you to three of them (plus a related fourth). Second, I’ll review a new science finding that raises deep questions about what, if anything, separates humans from other animals.

Some Books

Feminism in the wild: How human biases shape our understanding of animal behavior, by Ambika Kamath and Melina Packer, ties in nicely with my last substack on the four sexes of Ruff.1 Kamath and Packer open with the three sexes of salmon—cohoe salmon—to be precise. This salmon species has a sex variant that produces eggs (sex #1), and two that make sperm—a bigger more-errr-assertive Hooknose (sex #2) and a smaller, presumed-to-be-sneakier Jack that fertilizes broods when it can (sex #3). (Remember that these fish do not “have sex”. Instead the female releases a wad of eggs into the sea and the various males try to muscle in and layer on their sperm.) The usual story is that the Hooknose’s size and aggressive attitude attracts females, while the Jack only gets its way by sneak attack. Researchers who hold this stereotyped view often ignore observations on Jacks. The humans who run some fish hatcheries even prevent Jacks from fertilizing stock eggs. That is, having bought into the story that the large aggressive male is really the more “natural”, the human agents offer #2 an evolutionary boost by selecting against #3. Talk about playing G-d!

It turns out however, that if you include all the field observations, you can make the case that female salmon actually prefer the Jacks. So we have two possible stories: females prefer the big, aggressive fish and the smaller, quieter one has to sneak in for a quick lay. OR, the female prefers the smaller, quieter fish and the Hooknoses have evolved their size and power so that they can just overpower the beloved Jack. The truth is that we don’t know which story better reflects the Ms. Salmon’s POV because researchers’ gender stereotypical views have stopped them from making complete observations and entertaining more than one interpretation of the data.

Feminism in the Wild abounds with such examples. In diverse species the males battle each other for territories, tracts of land where they set up shop and optimize mating opportunities. With bluebirds, for example, scientists assumed that having a great territory attracted a female who monogamously devoted herself to raising HIS babies. Before the days of DNA identification, nobody could say otherwise, and the story of male as provider and female as devoted mother was compelling. It’s just that it wasn’t true. Once scientists could identify individual DNA profiles, they discovered—sometimes to the horror of their inner Victorian—that territory or not, females frequently mated with several males. In a bluebird nest those beautiful blue eggs often contained developing half-sibs; pater territorialis provided real estate for babes that he did not genetically father. Although, of course, his nest and food provision is an important—albeit non-genetic—form of fathering.

Kamath and Packer also delve into racial presuppostions in biology, and what I would call capitalist and colonial assumptions woven into evolutionary theory. The linking threads were developed by feminist scholars—a vibrant group of scientists, philosophers and historians who in the 1980s started to examine science itself. It is important to name names, and yes, I was one of this group. So too were Sandra Harding, who, sadly, just recently passed away, Donna Haraway, Ruth Hubbard and Helen Longino. In another recently-published book, Our science, ourselves: How gender, race, and social movements shaped the study of science (2024), science writer Christa Kulian illuminated the history of the East Coast (U.S.) wing of the feminist science studies movement. 2

What did these feminists conclude? The outcome of years of work and argument—like John Lewis’s good trouble, this was good argument— is easy to summarize. Scientists try to understand how the world works. But we come at it with preconceived stories (fancily called frameworks or theories), and we try to fit observations into the existing narrative. Feminist science studies theorists pointed out that stories about aggressive males and passive females were not the only possible ones, and that they not-so-weirdly looked a lot like Victorian era white, middle class gender norms. To improve science, scientists need to look through more than one lens, tell more than one story. Because in the end, better, more complete, narratives result. We can liken a story about aggressive, territorial males to a simple nursery rhyme. But what really goes on in the natural world is more akin to a complex novel. War and Peace, anyone?

In 1999, after about a decade of feminist science writing, historian Londa Schiebinger wrote a book called Has Feminism Changed Science.3 Schiebinger concluded that it did then, and Kamath and Packer make it clear that it does now.

Two other shiny new books pile on the evidence: when scientists become more aware of feminist, queer, gender-minority, non-white, anti-colonialist points of view, they look differently at information that has been there all along; they begin to ask different questions,and collect different kinds of data. In The Sexual Evolution: How 500 Million Years of Sex, Gender, and Mating Shape Modern Relationships (2025)4 Nathan Lents, a professor of biology at the City University of New York, shows how what was once a one-off—a heart-warming story, for example, about two male penguins falling in love and hatching an egg together,5 really is the tip of an iceberg of sexual variety and diversity in the animal world. Similarly, as Princeton University anthropologist Agustín Fuentes explains in Sex is a spectrum: the biological limits of the binary (2025), what was once a belief that intersex babies, and children who express transness at young ages, were medically distressed, has transformed into arguments for normal gender/sex variability.6

Well if the weather ever improves, all these books should make for some fascinating summer reading, keeping people stimulated as they soak up a few rays. But in the mean time, I have on immediate offer something amazing to think about.

Some Science

This finding addresses neither race nor gender, but another Big Question: what is it about humans that makes us think we might be worthy of holding dominion over all the other animals? 7 When I was in college my anthropology professor assigned a book by Kenneth P. Oakley called Man the Toolmaker . It offered the latest 1960s-era skinny about cultural anthropology. Nevermind the “Man” part of it. In those days scientists thought that tool making separated humans from the beasts. But then Jane Goodall watched chimpanzees use sticks to fish termites out of nests, and collect rocks to crack open nuts. Tool making was out. O.K. If not tool making, maybe language would fit the bill. But then whales and dolphins started communicating, elephants sent out low frequency rumbles that traveled underground, and a bonobo named Kanzi used pictograms on a keyboard to communicate with his human friend, Sue Savage-Rumbaugh.8 Language was out. And so the search continued.

In the end I don’t think there is an answer. There is no single trait that sets humans above all other beings. And you don’t have to take my word for. Philosophers and cognitive scientists are lining up behind this viewpoint.9 These days what I find fascinating is not what makes us different from other forms of life, but all the things we have in common. Along these lines, a recent article in Science bowled me over.10

I was leafing through the magazine when this photo (below) grabbed my attention. The caption explained that I was staring at a bystander mouse resuscitating an unconsious mouse friend by prying open the friend’s mouth, pulling on the little guy’s tongue and opening its airways. And said bystander mouse had never even taken EMT! I couldn’t not read the article that explained the photograph.

We’ve all seen heart-rending reels and you tube videos of animals interacting with an injured or dead companion. Usually it is a charismatic species—an elephant or a whale or a primate mother holding onto its dead infant. Are these just random anecdotes, or do animals routinely aid injured companions? And mice? Really?

To study rescue behavior more systemmatically, the authors of the Science article housed young mice communally. They also set up a separate test cage where they could video record rescue events for later analysis. One day they would put a subject mouse in a cage with an anesthetized cagemate; on a different day they offered a choice between the anesthetized cage buddy and an alert playmate. The rescuer most often chose saving its downed buddy over playing with an active friend, an choice made more likely the more familiar the rescuer was with the afflicted mouse.

If a mouse found its roommate from the group home lying, immobile, it groomed and bit it. If that didn’t cause the ailing victim to stir, the rescuer began mouth-biting, tongue pulling and even removed foreign objects from its air passages, all resulting in improved airflow to the lungs. Once the downed mouse revived, the rescuer stopped rescuing. The full article offered more detail and nuance, but that image of tiny little mouse hands prying apart the jaws of its unconscious companion sticks with me.

As is the style, the article’s authors concluded, rather formally and cautiously, “Our findings thus suggest that animals exhibit reviving-like emergency responses and that assisting unresponsive group members may be an innate behavior widely present among social animals. Such behavior likely plays a role in enhancing group cohesion and survival.” But I still can’t get much beyond “Wow! Look at that, a mouse doing mouth-to-mouth rescucitation!” We have more in common than we might think with those fuzzy little creatures who sometimes leave poppy-seed sized turds in our kitchen cabinets.

Others were outraged. I think it was denounced by the Vatican, but that happened so long ago that my memory is a bit hazy. More recently, in heated exchanges on platforms such as formerly known as twitter, correspondents accused me of lying, of ruining lives, refusing to accept facts and of being ignorant of biology, PhD in developmental genetics notwithstanding. Many pointed to the world of non-human animals, especially other vertebrates (since few find the world of aphid sex to be as much fun as I do1), as proof that there are two—and only two—sexes.

And of course, now the President of the United States has decreed that there are only two sexes and that the entired nation must be organized on that principle. Non-binary existence: forbidden. MAGA gender ideology to the fore.

But what are we going to do about the Ruffs, a medium-sized shore bird that nests in the arctic tundra? As you might expect, there are female ruffs. They have the brown and white speckled camofluage frequently sported by ground-nesting shorebirds—coloration that is hard to spot in the sand or brown vegetation. So that’s one sex. Then there is a male, called an Independent (a.k.a. Indy). He is the largest ruff and comes in spectacular, intricately-patterned breeding plumage. During mating season he and other males gather, strut their stuff, and—figuratively speaking—butt heads while females watch and decide who to mate with. The Independent, which makes up from 80-95% of the males, is sex #2.

The Satellite males (a.k.a. Sat), who make up from 5 to 20% of the males, also sport the eponymous ruff, but they are a bit smaller, less colorful, and less feisty than the Independents. They also occupy the multimale playing field and show off their feathers, helping to attract females. Occasionally they get to mate with one. They are sex #3.

Finally, there are the rare (maybe 1%) Faeder (a.k.a. Faed) males—so-called after Ye Olde English word for father. They are sex #4. They look a lot like the females and sneak onto the mating field unnoticed by the larger, more aggressive males. They may not fight, but boy do they have balls! In fact their testes are twice as large as the Independents’. They are what field biologists informally call “sneaky fuckers”. They blend in while the Indy guy courts a female. When Indy’s efforts get her all fired up, the Faeder dashes in and does the deed before the Independent knows what hit him (so to speak).2 The sneaky fucker tactic, by the way, in which an unobtrusive male mates with a female on the Q.T., is reasonably common in the animal world, and often involves a different look and a different behavior pattern.

How can it be that one species has three males that look and behave so differently from one another? During the last decade+ scientists who study this bird have laid it all at the feet of a particular supergene. Each of the male ruffs have a different version of the supergene. A single gene variant involves a small change in a single base pair in the DNA. Changes of this sort end up leading to a white instead of a red fruit fly eye, or lactose in/tolerance in humans. But a supergene is a whole chunk of DNA that contains many of those simple genes and can dramatically influence physical and behavioral development. There are several “in the weeds” questions about how supergenes evolve and anybody with an interest can read up on the ruff supergene in the references in notes 2 and 3 of this essay.3

Here I want to tell you a bit more about the relationship between a few of the regular genes housed in the Indy, Sat and Faed supergenes and steroid hormones—mostly testosterone (T) and its precursor, androstenenedione (A4). Our three males parcel out testosterone and A4 to their testes and circulating blood. Physiologists assume that hormones circulating in the blood can reach the brain and affect behavior4, while testicular hormones affect sperm production. The big picture point, to which I also return at the end, is that there is a lot of room for physiological variation in the sexual development of vertebrates. And it is all perfectly normal.

Hormones and behaviors: it gets complicated

First a little more about where each kind ofmale hoards his testosterone and his A4. The testes depend on the right mix of hormones for overall growth and for healthy sperm cell development. Hormones in the circulating blood affect the rest of the body, including the brain (although see note 4 below), which influences behavior. The testes of Mr. Faed and Mr. Sat have 7-8 times more testosterone than Mr. Indy and 20 times more A4, and, as I already mentioned, bigger balls to show for it. But what about T and A4 circulating in the blood stream? Here the Independent excels with high levels of T, although he doesn’t have much in the way of A4. At the same time the Satellites and Faeders have almost no circulating T but loads of A4.5

So, to summarize: Indys have low T in the testes and high T in the blood but not much in the way of androstenenedione. Sats and Faeds have high T in the testes, low T in the blood and are replete with A4 in both tissues. To figure out how these hormone patterns might correlate with mating season behaviors, researchers rated aggression (chase, peck, forward, and fight) and courtship (full squat, mutual squat, circle, half-circle, and mount) in videos of the three kinds of male ruffs .

The results are pretty interesting, and also leave us with some standing puzzles. Only the Independents showed aggressive behaviors, and they did so at the rate of 0.6 behaviors per minute. In addition to aggressing, the Indys courted at the rate of 0.2 behaviors each minute. But the Satellites courted even more, logging in at a rate of about 0.4 behaviors per minute. In contrast to both the Indys and Sats, the Faeders neither courted nor aggressed. Clearly, high T/ low A4 is associated with aggressive bird actions. Courtship, however, is more complicated. High T/low A4 (the Indys) correlates with some courtship behaviors while Low T/High AF is matched with high courtship behaviors for the Satellites but none at all for the Faeders. I don’t have an explanation for this difference in courtship between Sats and Faeds. Nor it seems, at least for now, do the researchers in question. (Researchers have their own frustratingly common behavior. If something doesn’t make sense, they simply don’t mention it, which left me spending hours trying to figure out what I might be missing. Grrr.) In an earlier paper they did worry about it and suggested some future lines of research that might solve the problem.

A little biochemistry can go a long way

But in the 2025 paper they focused more on a related question: how do the different males manage to set different levels of T and A4 in different tissues? To address this problem we need to return to the supergenes and ask how they regulate hormone synthesis.

I start with some basics: how do ruffs (and humans) make testosterone (and A4). Neither are direct gene products. There is no gene for testosterone. Rather, these two steroid molecules are assembled, step by step from a starter molecule familiar to most of us—cholesterol. We get cholesterol from our diet, and enzymes (proteins that facilitate a chemical reaction) help transform cholesterol into androstenendione and hence to testosterone. The image below is a simplified map of steps in this transformation. Here’s where the supergene comes in. Genes code for proteins, many of which are enzymes. And the supergene variants associated with the different ruff males code for a passel of enzymes each facilitating a step that turns cholesterol into testosterone.

The above (simplified) diagram names 7 of these (e.g. CYP17A1 and HSD17B3), coded for by 7 simple genes that are located within the supergenes. These 7 enzymes govern most of the steps taking cholesterol to testosterone.

The higher T in the Satellite and Faeder testis probably results from higher concentrations of three enzymes in the early part of the T-synthetic pathway, the steps that start the transformation of cholesterol to testosterone. But one enzyme—HSD17B2 (B2 for short)— at the very end of the pathway from cholesterol to T is the most likely culprit for the higher levels of circulating T in the Indy blood stream. B2 takes testosterone and turns it back into T’s precursor—A4. Because of the structure of the Indy supergene, B2 gene expression is negligible, so once they make testosterone they get to keep it. In contrast the structure of the Stat and Faed supergenes, the B2 gene is “highly expressed”. This means that even though their blood cells make T, the B2 enzyme converts it back to androstenenedione. The result: low concentrations of circulating T in Sats and Faeds.

Some Ruff life lessons

Living life—successfully accomplishing daily tasks such as resting, eating, relating to others and longer-term ones such as reproducing—is complicated. Problems arise—where shall I find food, or a comfortable spot to sleep, or can I (or do I want to) find a life companion? How can I raise myself from a sitting position, or lower myself to the floor from a standing one? For each problem there are many possible solutions. In this substack I focused on one big issue for ruff males—how do they manage to woo and mate with a female?

As a species , the ruff deploys three different approaches to mating. Each of the three approaches takes advantage of the huge flexibility inherent in biological organisms. To regulate hormones, each kind of male uses biochemical approaches to regulating hormone levels in different tissues. As a result, during mating season, each kind of male express different behaviors. Some males are found more commonly, others less. But each represents normal variation within the ruff population.

I don’t think humans are any different in principle. In fact we are way more complex than ruffs, and we have open to us a far wider range of possible behaviors, self presentations, likes and dislikes. Given what we know—what the ruffs tell us— about biological complexity and diversity within species even down to the level of individual genes, the idea that our best self-description is that there are two and only two sexes, types of desire, or “normal” physical appearances is—at the very least—improbable.

1

Wheat aphid life cycle

I case you hadn’t noticed, our country is in an uproar. Substackers are posting like mad. I carved out my little corner which addresses the uses and abuses, the ups and downs of science. But even here, there is too much happening. While I put together short pieces on gender/sex, diversity, equity and inclusion, and the occasional basic science report, 47 signs an Executive Order “Restoring Truth and Sanity to American History” and attacks museums for explaining how racial conflict and slavery have shaped the United States.

I can’t write fast enough. So I am happy when, from time to time, a colleague writes “a thing” (as he referred to it) and gives me permission to reprint it here. That colleague is the biological anthropologist Jonathan Marks. He is Professor of Anthropology at the University of North Carolina at Charlotte, and his most recent book is Understanding Human Diversity (2024). Thanks, Jon, for sharing!

Race and Science

By Jonathan Marks

The race controversy engendered by the recent Executive Order, “Restoring Truth and Sanity to American History” represents only one front in this administration’s general antagonism against science, and against specialized knowledge more broadly. Science is being catastrophically defunded, its facilities and offices in the government are being shuttered, and the field of higher education is in a general uproar. Truth and sanity are always welcome, but they generally represent what science is providing, not what science needs to have imposed upon it by decree.

Biological anthropology, the study of our species and its origin, has had two watershed discoveries. In the 19^th century, we learned that our species is descended from earlier, extinct species similar to living apes. In the 20^th century, we learned that race and human variation are quite different things.

By “race”, we generally mean the idea that the human species is composed of a fairly small number of fairly distinct kinds of people, each with their own inherent properties. It certainly seemed that way in the 1700s and 1800s. Over the course of the 20th century, however, anthropology began to ask the question, what would the human species look like if we removed the lenses of race from our own eyes? Would we still see it? And if not, what would we see?

The answer has emerged gradually over the last few decades. Groups of people are differentiated from one another primarily culturally, in terms of their language, belief systems, personal adornment, traditions, knowledge, tastes, family relations, and all of the other things that cultural anthropologists began to study intensively in the early part of the 20^th century.

Now if you decided, for whatever reason, to focus only on biological distinctions, ignoring the primary dimension of human variation, what would you see? Actually, you would see that you can't make that distinction so readily, because so much of human biology is in fact strongly influenced by culture, from the shape of your head to your likelihood of dying from tuberculosis. Human bodies indeed absorb a great deal of the cultural world.

But suppose, however perversely, that you decide to ignore both cultural differentiation and bodily differentiation, and decide to focus exclusively on the human gene pool. Would you see race there? And if not, then what would you see? And the big discovery of human population genetics towards the end of the 20th century was that you don't see race; rather, you see nearly all detectable genetic variations nearly everywhere. Human genetic variation is primarily polymorphic and cosmopolitan. However it is measured, upwards of 85% of the detectable human genetic variation is variation within groups rather than between groups. That doesn't mean that there are no geographical patterns, of course.

So if we ignore the cultural variation, the bodily variation, and the primary, polymorphic, pattern of genetic variation, and we decide to focus only on genetic variation from group to group, what patterns do we find? Is race finally there? No, we find gradual change across geographical gradients, a pattern that genetic anthropologists describe as clinal. We find that people are similar to those nearby, and different from those far away – although even then, only in an ideal, non-urbanized, precolonial world. The genetics of New York City is something else entirely.

“The lie of race is that it misrepresents the actual biology of our species.“

If we ignore the cultural, the physical, the polymorphic and clinal genetic variation, then what is left? Do we finally uncover the primordial human divisions? No, we find that there are all kinds of interesting local genetic patterns in the human gene pool, with different cultural identities being associated with different genetic histories and with different probabilistic genetic risks at present. But those different genetic risks don’t map on to race: Pennsylvania Amish have their risks (polydactyly); Ashkenazi Jews have their risks (Tay-Sachs Disease); Afrikaners have their risks (variegated porphyria); Northern Europeans have their risks (cystic fibrosis). Racializing these differences only confuses things. Sickle-cell anemia is found in Saudi Arabia and Greece, as well as in West Africa. Why? Because it is associated with malaria, not with being African. And these remain risk factors for particular populations, still afflicting only a small minority within each population – just simply a larger minority than in other populations.

When you look at the human species scientifically, this is what you find. It isn’t race. Race comes from somewhere else.

What then, do we mean when we say race is a “social construction”? We mean that it is a product of history, not of biology. What we have come to understand as race is the outcome of centuries of political relations between powerful Europeans and the less powerful – the English versus the Irish, the Christians versus the Jews and Muslims, European colonists versus Native Americans, traders versus African slaves. What they have in common is the formation of symbolic boundaries that function to establish and maintain inequalities. Those cultural boundaries sometimes correlate with biological features, which affords them some camouflage as apparent products of nature rather than of human invention. That is why even scientists were confused about it for two hundred years.

The fact is, however, that the average difference in lifespan between Blacks and Whites in America is due to racism, not to sickle cell anemia. The lie of race is that it misrepresents the actual biology of our species. The fact that race is also there to perpetuate injustice makes race less of a fact of nature, and more of a fact of biopolitics.

This administration isn't making human biology unpolitical, they are making it exactly as political as it always has been. In this case, their convictions about race are anachronistic and their scientific ideas are from an earlier century, which is why they need to be presented as an order, rather than as a discovery. There is no unpolitical human biology.

This definition bewilders me. So I begin instead with the Merriam-Webster Dictionary that says that ideology is “the integrated assertions, theories and aims that constitute a sociopolitical program” and—and I will return to this — “visionary theorizing”.

The EO seems to be saying that “Those people”, whoever they are (liberals? feminists? gender/sex activists? the Civil Rights Act?) have an ideology that is illogical and flies in the face of the known fact that there are two sexes and no gender. By implication, the authors of the EO have no ideology, just the truth about biology—there are males/men who have small sex cells and females/women who have big ones (WTF1 and WTF2). The equation reads: they have an extreme ideology while we have none. We have the truth. Follow us. Erase them. (And indeed the EO ends with a long list of documents and government websites designated for deletion).

The equation looks like a no brainer, except for one rather considerable problem: everyone has an ideology which structures how they interpret the world.

The EO’s gender ideology goes something like this: men and women are people with small or large reproductive cells. There is no normal variation. So, the rare person who doesn’t fit into this “two is normal” ideology—say an XY person with testes who looks and feels like a women (as in androgen insensitivity)— must be medically abnormal. Medical or psychiatric treatment might be appropriate but they (potentially) have those pesky small sex cells. So regardless of large breasts, or a vagina and a sense of self as female/woman they must be male/men. Such a conclusion results from the Executive Order’s gender ideology extremism that holds that there are only two sexes.

According to the EO authors’ ideology, claims to be normally non-binary sre fraudulent and possibly illegal. In recent times such claims gained legal validity, allowing gender-non-conforming people, for example, to obtain passports marked X for gender, or protecting them against discrimination in work, housing and schools. Or sports, which has freaked out a lot of people, and to which I will devote a separate substack. The current executive order pushes back on the idea that people all along the spectrum of human gender/sex/uality deserve legal protection and social recognition.

I also use a gender ideology to frame how I understand gender/sex variation. Rather than extreme, however, I see it as visionary, which is a second meaning offered by Merriam-Webster. I observe and analyze gender/sex variability as continuous, not either/or. Starting with physiology and anatomy I notice wide variation among people who the EO defines as female/women. Big breasts, small breasts, broad shoulders, narrow waist, large clitoris, small clitoris, long labia, short labia. The same idea holds for the EO-defined male/man. And then there are people with mixed reproductive anatomy or physiology—a penis and breasts, ovaries and testes, high testosterone levels and a “female” anatomy. And more.

There are heterosexual people, homosexual people, transgender people, bisexual people, etc. (the famous LGBTQI). A wide variety of desires, attractions and identities have always existed. In different historical eras they have been named differently, embraced, or rejected. Different cultures define and assimilate gender/sex variation in different ways. My ideology, as a biologist and also as a feminist activist, embraces the biological normality of human gender/sex variation.

Each gender ideology, my visionary one and their gender extremism, is compatible with a particular social vision.

An ideolgy of natural variation synergizes with a belief in social equality, a belief that generally, men and women (trans or not), people of whatever sexual orientation, deserve the same educational, job, housing, and travel opportunities. Everyone should be welcome in the public sphere. Everyone also has the right to control their own bodies— no forced sterilization, no forced pregnancies, no forced hormone treatments for rapists, and more. And speaking of controlling their own bodies, no matter how squeamish I may or may not feel about a particular voluntary medical procedure, it is not my job to interfere. I do not try to prevent straight women from getting breast implants or surgically modifying their vaginal labia. Or take hormones. Nor is it my business to intervene in affirmative care for trans people. The medical profession, in interaction with patients and group activists can judge these matters for themselves.

My social ideology and my scientific beliefs about gender/sex are intertwined. This does NOT mean that I ignore data. I believe deeply in empiricism. But my ideologies shape what I study and how I collect and interpret data. Just as my social theory focuses on human variation and equality, my biological theory leads me to look at how bodies change over the life cycle. I see that physiology responds to social context and developmental history.

The EO’s gender ideology extremism oozes out from their words and screams loudly from their enforcement actions. They start with word enforcement. From now on government websites and any government-supported research can only use the word sex. Gender has been banished, both as a noun or adjective and a concept. Gender, pregnancy, sex, male, female, care, breastfeed, diversity, and many more words have been scrubbed from government websites. The EO ideologues are even trying to prevent academic journals from publishing research on these topics.

The current U.S. government’s assault on gender/sex variation has been relentless. The State Department has confiscated trans people’s passports, ordering people to list the sex assigned at birth (although this phrase is now banned), even if they have legally changed their birth certificate. State is also preventing foreign LGBTQ people from entering the country. Now only EO-men and EO-women can serve in the armed forces. And the Defense and Health and Human Services Departments have suspended $175 million in grant money already earned by the University of Pennsylvania because they have one (did I say ONE?) transgender athlete on their women’s swim team. These are the tip of the iceburg in terms of instructions to erase gender/sex variation.

If this isn’t gender ideology extremism then I don’t know what is. This Executive Order calls out ideological extremism in unnamed others, when the order’s promulgaters are the real ideological extremists.

We need to have this conversation. The Times won’t have it. So we need to. The effort to stop federal and federally-funded institutions from attending to diversity, equity and inclusion comes from two places. The first, crass racism, is the belief that a person of color, a woman, a gay, lesbian or trans person, is inherently incompetent, that they could not safely land a plane no matter how educated they were, no matter if they went to MIT or Harvard. The second is that we should use the principles of white supremacy to organize government, businesses and educational institutions. In any organization, the white supremacist believes, a hierarchy should exist: the more critical, mentally taxing and high paid the job, the more only white men should be hired for it. In the early 20th century it was “No Irish need apply”; when I was a graduate student it was “find the best man for the job” (and “best” included skin color).

For most of America’s history white supremacy was the rule.1 This changed legally (and in many states) starting in the 1960s with the passage and modification of the Civil Rights Act of 1964. Under Title VII of this act hiring discrimination based on race, color, religion, sex, or national origin, is illegal. To enforce the anti-discrimination mandate the Act set up the Federal Equal Employment Opportunity Commission (EEOC). More laws followed. Now the EEOC is mandated to enforce “(1) the Equal Pay Act of 1963 (EPA), an amendment to the Fair Labor Standards Act of 1938 that prohibits discrimination on the basis of gender in compensation for similar jobs under similar conditions; (2) Age Discrimination in Employment Act of 1967 (ADEA) prohibiting job discrimination against persons 40 years of age and older; (3) Section 501 of the Rehabilitation Act of 1973 prohibiting employment discrimination against federal employees with disabilities; (4) Title I of the Americans with Disabilities Act of 1990 (ADA) prohibiting employment discrimination on the basis of disability in both public and private sectors, excluding the federal government; and (5) the Civil Rights Act of 1991 that includes provisions for monetary damages in cases of intentional discrimination.” 2

Diversity, equity and inclusion then, is not some left-wing whimsey. It is the law of the land. But that has only been the case for the most recent 25% of our history (using 1776 rather than 1619 as the start). The weight of national history still favors white supremacy, racism, sexism, homophobia, transphobia and all those other beliefs that interfere with inclusion and fair play in the public sphere.

It is time for some inward thought (each of us individually, and as a polity) and outward response. What if you have just boarded a large airplane and peeked in the cockpit as you passed and saw all those levers and dials and lights? You might think, wow, is that ever complicated. It must take good reflexes and simulation training, common sense, a high level of technal ability etc. to pilot this plane. And you are entrusting your life to the pilot. Then an African-American (or maybe Hispanic, or a white woman) pilot steps out of the cockpit. Are you suddenly worried? Would you ask to leave the plane unless the airline finds a white guy to fly it? In other words, how much have you (or any of us, and I include myself) interiorized the idea that only white men are truly competent for such an important task? Is our own failure to self examine the reason that attacks on diversifying our institutions seem to get so little push back?

It’s still relatively new, having an African-American or a white woman pilot a large commercial airplane. I notice when it happens. But I hope the day will come when it is so commonplace as to be unremarkable. And as a polity, we have something to say about this. Collectively, we can insist that our government continues to enforce the law, and insist on the principles as well as the moral righteousness of diversity, equity and inclusion. We need to call out the 47s and the Musks and their sycophants and back-up theorists, who have turned these three future-facing words into a set of initials that signal support for white/male supremacy and the re-establishment of racial and gender segregation. We need to say these words out loud. Every time. No initials. And remind people that they are Federal Law.

White supremacists, including those in the Oval Office and in the House and Senate, and those who have seized control of legacy media, want a world in which educational institutions offer preferential admissions to white men. When I was a graduate student (in biology) the Psychology Department at Brown University admitted 15 PhD students each year, the top five women and the top 10 men. Today that is illegal. The top 15 people must be admitted regardless of gender/sex or race. Medical schools had a 10% quota for white women and Jews and an even smaller one for African Americans. That too is now illegal. This is in my lifetime. I remember.

White supremacists want a world in which African-American women clean the TV studios but cannot anchor a Prime Time News Broadcast. And they want a world in which being female and/or non-white is a disqualification for becoming President.

THAT is why they are trying to cleanse websites of words such as women, black, gender, Native American, LGBT and, well, check out the list below. That is why they are attacking universities, civic organizations and businesses for following the law. That is why we have to keep asking which world we want—democractic and inclusive, or white and male supremacist. Which side are you on?