Category: sex and gender issues

Surprise! Agustín Fuentes and Nathan Lents criticize the sex binary

November 24, 2025 • 9:30 am

I don’t know how many times Agustín Fuentes, an anthropology professor at Princeton, will keep repeating the same arguments about why biological sex isn’t binary (see these posts on my site). It never seems to end. You’d think he’d stop banging the drum now that he’s written a whole book on the issue called Sex is a Spectrum, but he keeps on making the same old arguments that have been refuted many times (see this review by Tomas Bogardus, for example).  Why does someone make such weak arguments, and continue to do so without ever addressing the many criticisms he’s encountered?

I strongly suspect it’s because Fuentes is an ideologue: he believes that if people see biological sex as spectrum rather than a binary, opprobrium against trans people will lessen or vanish. But trans people should be treated with respect no matter whether or not sex is binary, for “is” does not equal “ought”—a lesson Fuentes should have learned. Further, nearly all trans people implicitly accept a sex binary: after all, they transition from having a male role or appearance to having a female role and appearance, or vice versa. But I’ve written about that before.  Nor does the binary nature of sex have anything to say about how we should regard people of nonstandard gender.Making that argument is another violation of Hume’s Law.

Now Fuentes has been joined by Nathan Lents, a professor at John Jay College. Lents has done good work refuting Intelligent Design, and I’m sad that this essay, published in ProSocial World, an endeavor of biologist David Sloan Wilson and colleagues, is not of Lent’s usual quality. In fact, it’s a terrible article, replete with mistaken arguments and bad logic.

Now it’s possible that these authors really believe that biological sex is a spectrum and are not just trying to buttress a “progressive” gender ideology, but I would find that behavior obtuse. Read Dawkins (link below) or Bogardus to see why.

I am so tired of this misrepresentation and confusion that it deeply nauseates me to have to discuss them again, but I’ll try to do so briefly, using quotes from the article by Fuentes and Lents. Click on the headline below to read (it’s also archived here).

Fuentes and Lents (henceforth F&L) first admit the binary of gametes, a binary used to define the sexes by most biologists who aren’t ideologues:

The major clades of eukaryotes – plants, animals, fungi, and the many kingdoms of protists – have evolved both unique and shared aspects in their sexual reproductive mechanisms, but one such aspect – the differentiation of gametes into two major forms – is a common theme. Anisogamy, the property of having two types of gametes – one very large and relatively immotile and one very small and highly mobile – is a key feature of sexual reproduction in all animals, all land plants, and many protist kingdoms.

F&L’s beef is not that there is a gametic binary (see Richard Dawkin’s great Substack essay for why defining—actually, recognizing—the sexes this way is essential and useful), but rather that organisms recognized as “male” (small mobile gametes) and “female” (large immobile gametes) show variation in other traits related to sex.  On average, human males differ in body size from females, but there is variation within each sex. And so it goes for body hair, gene expression, behavior, penis size, and so on.  But of course these traits, while correlated and connected with sex, are not part of the definition of sex, which involves the gamete binary.

Some quotes from F&L:

In our view, this binary classification of sex in animals is insufficient for capturing the full breadth of biological sexual diversity.

Some of the inadequacies of the binary sex classification for individuals are uncontroversial, as it has long been known that a large number of species – around 20% of non-arthropod invertebrates – include individuals that are simultaneously hermaphroditic. Many others, including around 2% of vertebrates, are sequential hermaphrodites. Animal bodies exist in a variety of sexed forms, with some even reconfiguring their biology relating to sex, including for the production of gametes, within their individual life history, sometimes multiple times. The presence of simultaneous and sequential hermaphrodites vexes the binary classification for sexed bodies and demonstrates that sex is neither immutable nor neatly reducible to gamete production.

Furthermore, sexual dimorphisms, sexual bimodalities, and a spectrum of sex-influenced gene expression are observed throughout animal bodies and across animal species. Some of this variation is patterned in close association with gamete production, but much is not so simply described. Across bodies, behaviors, and physiologies, there is substantive inherent variety and diversity, creating a sexual continuum of genetic, developmental, and behavioral biology within and across species. Individual animals can vary widely in the development, patterning, and expression of sexual biology in a variety of ways, from body sizes and compositions, to color patterns and genital anatomy, to courtship behaviors and parental investment, to name some of the most commonly diverse components of sex. These biological variations rarely collapse into two discrete sex-based categories defined by gamete production. Moreover, much of the biological variations in bodies, even those closely associated with reproduction, are also engaged in a diversity of other bodily functions and processes with myriad phylogenetic, ecological, and behavioral constraints and affordances, which are also not ubiquitously or consistently associated with the type of gametes a body produces.

But nobody contests this form of variation; but to pretend that hermaphrodites refute the sex binary is disingenuous. Yes, some individuals can make both types of gametes, and some, like the infamous clownfish, can actually change their sex, but the gametic binary remains. (I don’t much care if you call hermaphrodites a “third sex”, but they still bear only two types of gametes—the only types that exist.) Human hermaphrodites, like other individuals called “intersex,” are vanishingly rare, and none have been able to produce viable gametes of both types. But F&L’s arguments are not about hermaphrodites or “intersex” individuals with differences in sex development. Instead, their arguments are about variation among individuals, most of them of regular sex.

They also extend their argument among species. In various species of animals, for instance, biological sex can be determined by genes, chromosomes, rearing temperature, social milieu, haploidy versus diploidy, and so on, but there are only two types of gametes and reproductive systems, no matter how sex is determined.  That in itself should tell you something important about the binary.  Nevertheless, F&L persist with their “variation means there’s no binary” argument:

Dramatic sexual diversity and variation is not limited to adulthood. There is also substantive diversity in mechanisms of sex development across various animal taxa. There are chromosomal systems, other genetic systems, as well as systems based on season, temperature, age, social status, and population density, most of which have convergently evolved in multiple disparate lineages, emphasizing the relative genetic, cellular, and developmental flexibility and adaptability of these sex systems.

But, to paraphrase Ronald Fisher, the sexes are always two. Why is that?  F&L are using a familiar but misguided tactic trying to refute the sex binary. I call this “The Argument from Complexity” and it can be stated this way:

There is variation among individuals in traits related to and correlated with gamete type, and that variation is often not binary but bimodal or even forming a spectrum. Further, the determination of these traits, like body size or behavior, depends on a complex interaction between genes, development, and the environment.  Therefore biological sex itself is not a simple binary, but a spectrum.

You can recognize the fallacy in this; I believe Emma Hilton calls it a “bait and switch”. Yes, determination of ovaries and testes itself is complex, with many genes (as well as the internal environment) involved. And individuals vary in gene expression, body size, ornamentation, and other traits connected with sex. But there are still only two types of gametes and two sexes. Male and female peacocks look very different, but nobody says that refutes the sex binary. (In fact, the sex binary explains this difference.) And individuals of the two sexes must mate with each other to produce offspring—save for parthenogenetic or self-fertilizing species, which still participate in the gamete binary. Regardless of the complexity of development in humans, you get an offspring only when a male having sperm mates with a female having eggs.  If the male is very short, or has a tiny penis, that makes no difference!

Here’s F&L’s version of The Argument from Complexity:

Importantly, the recognition that sex can be a complex mixture of anatomy, physiology, and behavior does not serve to deny or minimize the existence and impacts of sex differences. In fact, it affirms them and emphasizes their importance. While the matter of which gamete an animal body makes – its gametic sex – is clearly important, it is not the only variable by which animal morphologies or behaviors can be, or are, sexed. If these other variables were neatly binary, immutable, and non-overlapping, it would not be necessary to distinguish between gametic sex and biological sex. But, since nearly all other sex traits are either continuous or bimodal, are not always immutable nor perfectly correlated, a simple and categorical definition of sex that is based purely on gamete production is both unwarranted and potentially misleading.

. . . Animal morphology and physiology are the product of complex interactions of biological, developmental, and environmental systems, and the human environment is a particularly complex assemblage of biotic and abiotic factors: what we refer to as human culture.  Human phenotypic expression is always mutually shaped by cultural milieu.  It is well-established that adult height and weight, childhood development trajectories, taste bud reactivity, muscle development and coordination, patterns of sexual arousal, resistance (or lack thereof) to disease-causing bacteria, and nearly every other aspect of human bodies emerge from mutual and interactive development of physiology, morphology, cultural context, and lived experiences.

All that is sand thrown into the eyes of the public; it has nothing to do with the binary nature of biological sex.

Finally, N&L even make the bonkers argument that the athletic advantage of males or females may not be a result of their evolved differences (based on gene expression), but could be a result of social conditioning. This is an argument made by those “progressive” individuals who think that we should not be dividing sports into male versus female leagues. (The Olympic Committee has just decided otherwise.):

Furthermore, it is not currently known which, or how much, of all of this patterned variation is shaped by differences in how boys and girls, and men and women, use their bodies on a daily basis. While human anatomical development is a fairly canalized pathway producing a relatively consistent phenotypic range, the developmental process itself both affects and is substantively affected by how that anatomy is physically and socially engaged, especially during childhood and adolescence. Indeed, there is emerging evidence that persistent culturally mandated gender differences in play behaviors and sports participation, which are quite substantial in many cultures, have clear and strong effects on the developmental dynamics of skeletal and muscle formation.

Similarly, gendered differences in the social environment likely contribute to differences in sexed bodies in ways that are probably impossible to untangle. For example, it is well established that hormone levels and ratios are affected by the social environment, and these same hormones directly impact both the development of many tissues and sex-related and non-sex-related behaviors (muscle hypertrophy, hair distribution, metabolism, mental alertness, and libido, to name a few). Such complexities are not limited to humans by any stretch, as Patricia Brennan explains in another essay in this series, in Ruddy Ducks, social interactions directly impact the seasonal growth and development of the penis, emphasizing the dynamically responsive nature of sexual anatomy, even in adult animals.

It’s not clear to me what the penis of ruddy ducks has to do with human behavior and sports participation. Sadly, F&L don’t discuss the evidence that even injecting biological males with hormones and giving them puberty blockers, an important change of internal environment, nevertheless still gives these trans-identified males an athletic advantage over biological women.

I hope that I don’t have to make these points again, but I suspect I will.  The ideological termites have dined well, and have even managed to convince biologists and science popularizers like Steve Novella and Bill Nye that sex is a spectrum.  Have a look below at Bill Nye using the Argument from Variation to claim that sex is a spectrum. (I have never liked his arguments, and this bit shows he’s drunk the Kool-Aid.)  Nye also notes that sex is “assigned at birth”.  What is extra confusing is that he conflates sex with both “sexuality” and gender.

Joan Roughgarden and Jaimie Veale on sex and gender

November 20, 2025 • 9:45 am

This op-ed piece in the San Francisco Chronicle is by two academics, Joan Roughgarden, whom people here might know (I reviewed her book Evolution’s Rainbow in the TLS), and Jaimie Veale, who are identified in the piece like this:

Joan Roughgarden is a professor emerita in the Department of Biology at Stanford University and author of “Evolution’s Rainbow: Diversity, Gender and Sexuality in Nature and People.” Jaimie Veale is a senior lecturer at the School of Psychological and Social Sciences at the University of Waikato in New Zealand and a past secretary of the World Professional Association for Transgender Health.

As Wikipedia notes, “In 1998, Roughgarden came out as transgender and changed her name to Joan, making a coming out post on her website on her 52nd birthday.”  Jamie Veale‘s gender is not public, but she (Wikipedia refers to Veale as “her”) is described as researching transgender health and other issues. But their own identification, while perhaps motivating the thesis of this short letter, is hardly relevant to discussing the issues below. Click the headline to get the archived version, as the Chronicle’s own version is paywalled. 

Roughgarden and Veale (henceforth “R & V”), make a number of statements, some of which I agree with and other which I don’t, but overall they made me think about the differences between (biological) sex and gender.

First, they agree that sex is defined by gamete size, something that Roughgarden, to her credit, has always admitted:

Zoologists, botanists, ecologists and evolutionary biologists generally define sex in this way: males make small gametes (sperm), females make large gametes (eggs) and hermaphrodites, such as most plants and many marine animals, make both.

Many animals change sex, such as coral reef fish that switch from making sperm to making eggs, or the reverse, during their lives. In turtles and other reptiles, sex is determined by the temperature at which eggs are incubated. Thus, sex may be determined well after conception according to social and environmental circumstances. And in humans, gamete production does not occur at conception. Various precursor stages appear in the fetus weeks after conception and gamete production awaits puberty.

I would note, though, that sex in humans, which is what everyone’s interested in, is determined at fertilization: whether or not the fetus has the Y-linked SRY gene that is the trigger male development.

But they also claim that every trait other than gamete size is not part of sex but is part of gender:

Beyond gamete size, everything else — including secondary sex characteristics, body size, shape, color, behavior and social roles — is gender.
Gender in nature is also extraordinarily varied and fluid across plants and animals, including humans. Beyond gamete size, no general binary describes how living things look, act or relate to others. Across species, gender difference ranges from penguins with near identical male and female genders to the extreme dimorphism of lions. Human gender diversity is in the middle, showing some gender difference that varies within and across cultures.

Thus whether or not you have a penis or vagina (secondary sex traits) are, assert R&V, part of your gender, even though their presence, and the other traits mentioned, are highly correlated with biological sex.  The idea that physical traits are part of gender seemed wrong to me, but the notion of what “gender” really is has eluded me for a long time.  So I thought about why it seemed wrong to call physical traits parts of gender instead of sex (behavior, as I note below, is a partial exception). This led me to come to my own tentative definition of gender.

The first thing I did, of course, was look up “gender” in the Oxford English Dictionary.  Virtually all the definitions had to do with the classes of nouns in languages in which words have genders, like French and German. But there was one related definition that did correspond pretty closely to what I see as gender: gender identity.

Oxford English Dictionary’s definition of gender identity:

An individual’s personal sense of being or belonging to a particular gender or genders, or of not having a gender.

Gender identity is generally regarded as distinct from biological sex, or sex as registered at birth. In later use it is also often (and for some commentators controversially) distinguished from gender as a socially or culturally constructed state (cf. gender n. 3b), and from its manifestation in gender expression or presentation (see gender expression n., gender presentation n.).

Thinking further, it seemed to me that gender identity (what people mean when they self-describe their gender) is a psychological rather than a physical trait: it is how someone feels vis-à-vis where they lie the spectrum between being masculine or being feminine. Or perhaps they feel they aren’t on that spectrum at all, or are somewhere in the middle.  Now of course in this sense gender can be described as “biological,” but only in the sense that all human thoughts and feelings are biological because they reside in the neurons of the brain.  But otherwise, you can’t tell someone’s gender by their behavior, genitalia, body size, etc.  You can’t tell what self-conception a person has who possesses a penis and a beard, because you can’t see inside their brain.  Most such people, of course, are of male sex and feel themselves to be pretty close to male on the psychological spectrum, but traits besides gametes are not dispositive of gender. You  would find out someone’s gender not by observing them, but by asking them.

Behavior is a slightly different issue since behavior issues from one’s self=conception. So R&V are correct in saying that historically, different genders have characterized many societies—though I’m using gender in my sense and not theirs:

Across cultures and through time, societies included people corresponding to what the West now calls trans or gender diverse. Anthropologists and historians documented these people across North America, South America, Polynesia, India, Southeast Asia, ancient Rome and other parts of the world. Many cultures accepted these individuals as simply part of everyday life, often holding respected social and spiritual roles unique to their cultures.

I agree with them so long as you consider gender a psychological and not physical feature, and one that can but not necessarily is expressed visibly through behavior. In other words, gender is your self-identification in terms of how you fit on the sex spectrum (or off it), and gender roles are how those self-identifies are acted out in society.

But I disagree with the authors on two issues. First, on their claim that gender identity should somehow be recognized by the courts:

In matters of law and policy, “sex” actually refers to elements of gender because the criteria that have historically determined one’s “legal sex” (typically genitals, chromosomes, appearance and/or behavior) are properties of gender and not sex. As such, the courts should recognize that legal sex encompasses gender diversity.
The authors aren’t clear about this, but it could mean that they think that biological males who identify as being women should be able to enter women’s spaces, including prisons or sports leagues, or have a right to do rape counseling if a woman wants a biologically female rape counselor. If that’s what they mean, then no, you need to recognize biological sex alone rather than gender. But I do agree with the authors’ final statement that you should follow the Golden Rule when it comes to gender identity: treating others as you would like to be treated if you were such people. (The exception, of course, are the stuff like sports and prisons).

Second, the authors seem to imply that “affirmative care” (they call it “appropriate care”, though I’m not sure that’s what they mean) is mandated for all young people suffering from gender dysphoria:

Today, every major U.S. medical association — the American Medical Association, American Psychiatric Association, American Psychological Association, Endocrine Society, Pediatric Endocrine Society, American Academy of Pediatrics, American Academy of Child and Adolescent Psychiatry — supports transgender people and their right to appropriate care. Still, if the medical establishment can switch from pathologizing trans people to supporting them, it could switch back under political pressure.

If “appropriate care” means “psychological care up to a certain age—the age when those with dysphoria can decide whether to take hormones or undergo surgery”—then I agree. But if they mean “affirmative care,” in which the wishes of children or adolescents are accepted and acted on therapeutically and medically, then I disagree.  I favor “objective” therapy, not “affirmative” therapy, but therapy done with empathy. But I do not sign onto the use puberty blockers or surgery until a patient is of an age of consent (18 or 21; I waver).

I find the article confusing, both in R&V’s definition of gender and in how they want it to be used in law. There are some people—I believe Alex Byrne is among them—who say that gender is really a word that has no real meaning (it’s analogized to a “soul”).  But there is still the phenomenon of people who don’t feel they adhere to concepts of masculine or feminine psychology, and I’m groping to find a definition of “gender” that can describe such people. (Most of them are, of course, biologically male or female using the gametic definition.)

Feel free to give your own take on gender in the comments. But remember, be civil and don’t call anybody names!

Coleman Hughes interviews Carole Hooven

November 12, 2025 • 9:30 am

Here’s a 1.5-hour interview of biologist Carole Hooven by the Free Press’s Coleman Hughes. As you may know, Hooven got her Ph.D. at Harvard, started work as a teaching fellow in biological anthropology, and subsequently wrote the excellent book T: The Story of Testosterone, the Hormone that Dominates and Divides Us (2021).  She was apparently a superb and popular teacher, nabbing a lot of teaching awards. But then the downfall: she got into trouble after she went on a Fox program and spoke the truth, asserting that there are two biological sexes—carefully adding the caveat that pronouns should be respected and that people with non-standard genders should be treated equally. (You can see the 4-minute Fox interview here.)

But of course the assertion that there are two biological sexes, although true, gets you labeled a “transphobe” (even with the proper caveats), and the DEI people in Carole’s department eventually made it impossible for her to work there, so she left.  Harvard should be ashamed of this, and the school has done nothing to rectify its misbehavior. Subsequently, others have been demonized or called “transphobes” for defending the two-biological-sex fact. The demonizers, which include people like Steve Novella and the co-Presidents of the Freedom from Religion Foundation, should also be ashamed of their misbehavior, but they are seeking props for putting ideology over biological truth.

Carole begins by recounting her checkered—or should I say “diverse”—career, describing what happened at Harvard, and then explains the gametocentric definition of sex rejected by gender ideologues.  The rest of the interview, with both discussants showing their characteristic eloquence, is a biology lesson, a lesson on sex determination, what can go wrong with the “normal” forms of development, and how evolution has produced differences in the morphology and behavior of the two sexes.  Testosterone naturally makes an appearance.  You can see why Carole won so many teaching awards.

The YouTube notes are these:

In elite circles, it has become strangely difficult to say out loud what every biology department taught as recently as 10 years ago: that sex is binary, that testosterone matters, and that average differences do not mean categorical rules. That’s why I wanted to sit down with Carole Hooven, an evolutionary biologist who spent 20 years at Harvard teaching hormones, behavior, and evolutionary psychology before she was pushed out for stating precisely that.

In our conversation, Hooven traces how she got here: from her early fieldwork studying chimp aggression in Uganda, to her best-selling book on testosterone, to the moment a single Fox News clip triggered a campus-wide effort to paint her as “dangerous.” She explains what research actually says—about rough-and-tumble play, aggression, libido, and the long-run effects of puberty blockers and cross-sex hormones—and how activists and journalists systematically mislead the public.

Hooven isn’t angry or ideological; she is empirically careful. She draws a distinction almost nobody in public debate seems capable of holding anymore: Sex itself is binary, but sex-associated traits form overlapping distributions. Confusing those two ideas is what produces so much intellectual chaos and so much institutional cowardice.

This episode challenges the comforting myths: that these debates are “just semantics,” that biology can be legislated away, and that open scientific inquiry can coexist with fear of one’s students. What Hooven makes clear is that the science hasn’t changed, only the cost of talking about it.

Once again: Why there are two sexes and no more

November 6, 2025 • 9:50 am

In a recent post on his site “Reality’s Last Stand,” Colin Wright reprints an article he published a few months ago in Archives of Sexual behavior, outlining why there are exactly two sexes and dismantling five common arguments that biological sexes actually comprise either more than two types or a spectrum. Click below to read it or find the free pdf here.

If you’re already familiar with the rebuttals of the more-than-two-sexes arguments, you may want to skip this, but it’s a very short piece and worth refreshing yourself. And it was, of course, peer-reviewed.

I’ll give a few excerpts, listing the five arguments supposedly fatal to the only-two-biological sex view and making a few of my own comments. Wright’s excerpts are indented, and my own commentary is flush left.

He begins with what we all know is true: the two-sex definition (really a “recognition of reality”), based on differences in gamete size, was the accepted view until recently, when gender transformation became common, making people want to redefine biology to conform to their own views or identity.

In recent years, however, this previously uncontroversial fact has been challenged in popular discourse (Fuentes, 2023; Kralick, 2018; Viloria & Nieto, 2020) and now increasingly in scholarly scientific publications (Ainsworth, 2015; Fuentes, 2025; McLaughlin et al., 2023; Velocci, 2024), seemingly driven by cultural and political debates surrounding the concept of “gender identity” and transgender rights. Popular outlets now routinely publish articles asserting that there are more than two sexes or that sex is a nonbinary “spectrum” conceived as a continuum or as a multivariate cluster of traits. Scholarly articles have amplified this framing by characterizing the sex binary as overly simplistic, outdated, and even oppressive, urging its replacement with broader and putatively more nuanced models (Ainsworth, 2015).

Here I synthesize evolutionary and developmental evidence to demonstrate that sex is binary (i.e., there are only two sexes) in all anisogamous species and that males and females are defined universally by the type of gamete they have the biological function to produce—not by karyotypes, secondary sexual characteristics, or other correlates.

“Anisogamous” species are those having different sizes of gametes, and comprise all animals and vascular plants. That of course includes humans. And again, although the sperm vs. egg dichotomy is called a “definition” of biological sex, it recally should be called a concept because, like biological species, it simply recognizes an existing dichotomy and does not impose arbitrary human views onto nature.

Wright goes on to define biological sex, which has evolved several times independently. But isn’t it curious that each time it does—no matter what determines sex—there are only two classes that result? That’s an insight that has led to the creation of good theories for why the sexes are always two.  Here’s what Wright sees as the most common attempts to refute the sex dichotomy, and why they fail. Bold headlines are my characterizations.

a.) There are more than two “sexes” in organisms that have gametes of equal size (“isogamous species”), including some fungi and slime molds

. . . . sexes in anisogamous taxa are defined by gametic dimorphism—the production of small gametes (sperm) versus large gametes (ova). Some anisogamous species may also possess mating-type systems layered on top of male and female functions, but isogamous species, by definition, lack sexes.

Claims of hundreds or thousands of sexes thus refer to many mating types in isogamous systems, not to sexes. Where reproduction is anisogamous, the number of sexes remains two—male and female—defined by gamete type (Lehtonen, 2021).

This may seem like a slippery definitional ploy, but in fact biological sexes were recognized as being of only two types in anisogamous species, not isogamous species. Still, if someone insists on saying that there are many sees in isogamous species, I am not going to argue with them too vehemently. The claim of more than two sexes, of course, is invariably used to apply to animals and plants, especially humans. And there we see only two mating types.

b.) If you define sex by chromosome types, there could be more than two sexes. (Note, though, that many species with two sexes do not have them determined by chromosomes: in turtles sex can be determined by temperature, and in some fish by social hierarchies. ) In humans, for example, the typical XX (female) and XY (male karyotype) are supplemented by rare karuyotypes like XO, XYY, XXY, and others.

Colin:

The fundamental flaw is conflating how sex is determined with how it is defined (Capel, 2017; Griffiths, 2021; Hilton & Wright, 2023). In developmental biology, sex determination refers to the mechanisms that trigger and regulate sexual development. These mechanisms vary widely across taxa (Bachtrog, 2014). Examples include chromosomal (e.g., SRY gene on Y chromosome in mammals), temperature-dependent (e.g., higher temperatures produce males in many reptiles), haplodiploidy (e.g., unfertilized haploid eggs yield males in most Hymenoptera insects), or environmental (e.g., chemical cues in Bonellia viridis).

Yet, regardless of the mechanism by which sex is determined, an individual’s sex—male or female—is universally defined by the type of gamete (sperm or ova) their reproductive system has the biological function to produce (Goymann et al., 2023). Sex chromosome aneuploidies therefore represent variations within the two sexes, not additional sexes.

c.) Sex is a spectrum because individuals have a continuity of male and female traits, as exemplified by individuals having DSDs (differences/disorders of sex development.  As I’ve noted before, the frequency of “intersex” individuals, which supposedly cause the spectrum, is quite low: about 1/5600 individuals—close to the probability that if you toss a nickel in the air, it will land on its edge. Yet we don’t see people flipping coins saying, “Call it: heads, tails, or edge.”

. . .The primary evidence invoked to support the spectrum model is the existence of disorders/differences in sex development (DSDs) (Sax, 2002), including forms of genital or gonadal atypicality, often presented visually along a continuum from “typical female” to “typical male.”

However, the existence of such conditions does not undermine the binary nature of sex, because the sex binary does not entail that every individual can be unambiguously categorized as male or female. Rather, the claim is that in anisogamous organisms there are only two gamete types, sperm and ova, and thus only two sexes. Sexual ambiguity is not a third or intermediate sex because developmental variation does not correspond to producing new gamete types.

These next two objections are those I see most often in the literature, and they both have the problem that they don’t set out criteria for defining or recognizing someone as male or female.

d.) In reality, sex is a “polythetic” category, which Colin defines as “one in which members share overlapping characteristics, with no single feature necessary or sufficient for membership. Inclusion is based on “family resemblance”. This is the objection raised, for example, by people like Steve Novella and Agustín Fuentes.

Proponents of a polythetic sex model draw on this idea to portray sex as multivariate (rather than univariate, as in a simple “spectrum”). On this view, “sex” is an aggregate of traits—chromosomes, gonads, gametes, hormones, neuroanatomy, secondary sex characteristics, and other sexually dimorphic traits—and individuals are assigned degrees of maleness or femaleness according to how their overall profile aligns with what is considered male-typical or female-typical (Dreger, 2000; Fausto-Sterling, 2000).

However, male and female are not polythetic categories. They are reproductive classes defined by a single criterion: The type of gamete (sperm or ova) an organism’s reproductive system has the biological function tomproduce. All other traits—karyotype, genital morphology, hormone profiles, neurological and somatic dimorphisms—are typically causes, proxies, or consequences of that functional distinction. Treating those correlates as jointly definitional blurs the determinants and downstream effects of sex with sex itself.

e.) You can be a member of different sexes depending on which trait you’re looking at (chromosomes, genitalia, hormones, and so on).

As articulated by McLaughlin et al. (2023), sex is framed as “a constructed category operating at multiple biological levels,” with four focal levels: genetic, endocrine, morphological, and behavioral. This framing conflates the determinants and correlates of sex with sex itself (Bachtrog, 2014; Capel, 2017). Genes and gene networks initiate and regulate sexual differentiation; hormones mediate downstream development and phenotypic dimorphisms; morphology and many behaviors are influenced by an organism’s sex. Yet none of these traits defines sex. Sex is an organism-level reproductive class anchored to the type of gamete that organism has the biological function to produce. Treating upstream regulators (e.g., SRY activity, hormonal milieu) or downstream outcomes (e.g., dimorphic morphology, behavior) as coequal “levels” of sex is a level-of-analysis error.

And the kickerm which shows the fact that critics really do recognize two sexes (and use them in their own scientific papers!):

Moreover, the multilevel account inherits the same circularity as the polythetic model. Traits are labeled “male-typical” or “female-typical” only because they correlate with organisms already identified as male or female—an identification that, in anisogamous species, is made ultimately by reference to gametes. Once that reference is removed, the typology loses its interpretive footing. As a descriptive framework to integrate genetic, endocrine, and morphological findings in clinical differential diagnosis, the multilevel schema has pragmatic value; as a definition of sex, it is incoherent.

Why is this important biologically? Colin explains:

The scientific value of clear and precise definitions is enormous (Dawkins, 2025). A gamete-based definition prevents error propagation across comparative biology, physiology, ecology, and medicine. It preserves the interpretability of sex-linked phenomena—sexual selection, dimorphism, and life-history trade-offs—and maintains conceptual discipline by keeping determination mechanisms (e.g., SRY pathways, ZW systems, temperature-dependent determination, social cues) in their proper explanatory lane. It also secures cross-taxon coherence: Whether a species is gonochoric or hermaphroditic, and whether determination is chromosomal, environmental, or social, “male” and “female” remain meaningfully comparable because those terms are anchored to reproductive function rather than to a bundle of traits that shift widely from taxa to taxa.

I like to summarize this by saying that the biological sex definition/concept is both universal and explanatory. No other concept of sex, for example, can explain sexual selection and the differences in behavior and phenotype that appear in animals.

It’s important to recognize that the recent reframing of the two sexes as needing revision did not result from any new discoveries about biology. All the things about sex determination and differentiation have been known for a long time. What has changed is not biology but ideology. It is perfectly clear that arguing that there are more than two sexes is derived from the desire to give solace to those who don’t feel or identify as male or female,  But there’s no need to  change your view of nature to bring such solace. As Wright says:

The societal and ethical stakes are also significant. Accurate biology is distinct from questions of dignity, rights, and how we treat one another. Policy disputes should not be adjudicated by redefining—or defining away—the reproductive realities that make sex a useful scientific concept in the first place. When categories are blurred for nonscientific reasons, we invite downstream harms: muddled clinical protocols, compromised epidemiology, eroding and/or conflicting legal protections, and diminished public trust in science.

It is not transphobic to recognize the two sexes that biologists have known for decades, but, unfortunately, we are dealing with ideologues who are largely impervious to both facts and reason, and so the five points above are aimed largely at those who don’t know a lot about the way biologists conceive of sex.

Colin Wright on trans data epistomology: a new “way of knowing” that prioritizes ideology over truth

November 4, 2025 • 11:00 am

One of the recurrent themes on this site—and in the new anthology The War on Science, including the paper byLuana and Maroja and me—is the erosion of scientific standards by ideology.  Now a new paper in the peer-reviewed journal Big Data & Society (first title below), analyzed by Colin Wright on his website (second title), shows more than anything the explicit antiscientific aims of some ideologues. And those aims include clear guidance to prioritize ideology and politics over truth. Nowhere else have i seen this aim stated more blatantly.

In this case, the ideology promoted to distort or efface truth is “trans data epistomology”: a way to deal with data on trans issues. (As you know, empirical data, because they sometimes counteract accepted trans ideologies, have been controversial, leading to withholding of data that has real effects on human beings.)

I hasten to add that the distortion of data and prioritizing of politics over truth can be and has been applied to any group that does “science” with a political agenda—not just minority groups but entire organizations like scientific journals, medical schools, and professional organizations.  I emphasize this because trans matters are the hottest of political hot potatoes, but what this paper exemplifies is not at all unique to trans issues, and calling it out is not “transphobic”. In this time of extreme political division, science has become a tool not for finding truth, but for advancing your cause, no matter what the cause may be. Damn the truth, and full steam ahead.

The authors of this paper (again, it’s peer-reviewed) conducted 13 interviews of activists involved in “trans community care” and, from the 16 people involved in these interviews, the authors derived four pillars of what they call “trans data epistemology”, which turns out to involve, as Colin notes, ways you can use data to advance your cause.

Click the title below to read the paper:

Here’s part of the abstract; I’ve bolded the four pillars, but pay attention to the third one: “community well-being is more important than ‘accurate’ data”.  The last one, “data makes us visible to institutions,” apparently means “reframing your data in a way that serves your needs.”

 Drawing on literature from trans theory, data activism, critical data studies, philosophy, and critical social theory we offer a narrative of trans people as creators of knowledge, data-based and otherwise, undergirded by four pillars of a trans data epistemology: categories are provisional and productive, data can be a tool of community care, community well-being is more important than “accurate” data, and data makes us visible to institutions.

This is from the paper’s section on “pillar 3”: prioritizing ideology over truth:

Community well-being is more important than “accurate” data

Trans communities are experiencing an emergency. Well, it was already an emergency, but this is an epidemic. This is a crisis. This is, stop what you’re doing. We have to help now, today. And sometimes these pieces of data really can be a very strong call to action. (George)
In this pillar, we examine how participants prioritized actionable data for the trans community. Our participants reflected an understanding of data as rhetoric, as merely “one mode of conveying information” (Haarman, 2021: 35), not the only mode. When data is simply one of many ways of conveying information, it does not need to be viewed as the canonical source of truth. Our participants repeatedly emphasized that actionable and useful data for community care was the utmost priority over true, accurate, or verifiable data. We do not mean to undermine the meticulous data work of our participants but to emphasize the desired outcome of community well-being of their data work. This aspect of trans data epistemology is consonant with the idea that data is for community care.

This is an academic way of saying that there are other ways of knowing besides the data itself, and data doesn’t have to be the “canonical source of truth.” In fact, when the data conflict with “community care,” you give priority to the latter.  For things like “affirmative care” in gender medicine, this has obvious implications. One example is the withholding of data that counteract accepted ideology, like recent data showing that untreated gender dysphoria does not increase the suicide rate, or that affirmative care does not bolster mental health.

I’ll leave you to read the paper itself and Colin’s analysis below (I’ll quote him a bit), but want to add one part of the paper that’s becoming increasingly commonplace: “author positionality”—statements in which authors reveal aspects of their personal life, including their activities and ideologies. Here’s the positionality statement of the second author from the University of Washington (the first author works at MIT):

Amelia Lee Doğan: I came to this project after its development as a trans person interested in activism and data. My experience include working part-time for a university LGBTQ+ office for several years and researching other activists communities’ data and technical needs. I had no direct contact with any of the interview participants but their words and work truly made me cry at how other trans people are making this world a little better for us. Especially, as a trans young person of color, it was an honor to get to hear our elders talk about how they have fought and continue to fight and care for us.

Stevens’s statement is pretty much the same, except for the crying part. But is it any wonder that authors so deeply dedicated to a specific ideological aim are willing to allow distortion of data to achieve that aim?

On his site Reality’s Last Stand, Colin gives a succinct and, in my view, an accurate summary of the paper and its problems. Click below to read it:

I’ll give a few quotes, but if you like Colin’s analysis and work you should subscribe to his site.

Over the past few decades, universities have churned out a steady stream of papers so detached from reality that they often read like parodies. Many of them have been highlghted right here on Reality’s Last Stand: the infamous “feminist glaciology” paper that sought to “decolonize” ice; the surreal paper where two “hydrosexual” researchers married brine shrimp and made love to a lake; and the deeply disturbing pieces on “queering babies” and questioning childhood sexual innocence. Those were insane. Others—like those calling to “Indigenize” and “decolonize” medicine by rejecting the scientific method—are not just ridiculous, but genuinely dangerous.

Now, a new peer-reviewed article in Big Data & Society breaks new ground by openly arguing that lying with data is not only acceptable but morally required when it comes to transgender issues.

The paper, titled “Trans Data Epistemologies: Transgender Ways of Knowing with Data,” was written by Nikko Stevens, an assistant professor of statistical and data sciences at Smith College, and Amelia Lee Doğan, a PhD candidate at the University of Washington and research affiliate with MIT’s Data + Feminism Lab. What makes this paper truly remarkable is how the authors openly admit that “truth” in their work takes a back seat to politics. “Actionable and useful data for community care,” they write, is “the utmost priority over true, accurate, or verifiable data.”

They are so ideologically blinkered that they’re not even hiding the fact that they’re committing research misconduct. They’re openly celebrating it in a peer-reviewed journal. The very existence of “data activism” as an academic field shows just how thoroughly higher education has been captured by ideology.

. . .The paper presents this approach as a “trans data epistemology,” supposedly a new “way of knowing” based on “trans experiences.” The authors argue that “mainstream Western epistemology”—the normal way of doing science—has historically favored the perspectives of the dominant group—white, cisgender, heterosexual men.” Because there’s “no universal knowledge system,” they claim, “epistemologies based solely on the perspectives of one group are necessarily limited and incomplete.” Every group must therefore have its own truth, and the truth according to marginalized groups trumps all others.

In other words, they believe truth itself depends on identity. Instead of minimizing bias, as real scientists strive to do, these authors maximize it.

Colin goes through the four pillars of the new epistemology, which remind me of the indigenous “ways of knowing” capturing New Zealand. Colin views the new epistemology as “an assault on the scientific method itself, and it erodes public trust in the very institutions built to safeguard truth.”  Note that this assault comes from the left flank of politics.

There’s a lot more, but I’ll just give Colin’s conclusion and, below that, one of my favorite quotes about science.

Colin:

Underlying all of this is the belief that scientific standards are oppressive. The authors proudly conclude that their “trans data epistemology stands apart from hegemonic values about data, in which data is a mimetic representation of reality [and] a way to discern truths about the world through big data insights.” The idea that “represent[ing] reality” with data is “hegemonic” is absurd.

It’s hard to overstate how blatantly this paper rejects the basic principles that make science possible. Principles that have slowly evolved over centuries to reduce bias and uncover truth. That this paper survived the gauntlet of peer-review at Big Data & Society—supposedly a top journal in the field by impact—shows just how far the academic world has fallen.

And Richard Feynman, on the Challenger disaster:

For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.

The only silver lining to this dreadful paper is that hardly anybody will read it, as it’s buried in a rather obscure journal. On the other hand, people need to know stuff like this so they can see how real, objective science is going down the drain, washed away by the shower of ideology. And “regular” people are starting to realize this because some ideological nonsense, like the view that there is a spectrum of biological sex in humans, has made it into the public ear.

Shame on this journal, and shame on the peer reviews who denigrate truth in favor of politics.

The erosion of medical journals

October 28, 2025 • 11:30 am

Of all the papers in the special issue of the Journal of Controversial Ideas on censorship in science, the one below is perhaps the most important, as the censorship being imposed can cause permanent damage to humans. I’ve described this censorship before: it involves papers on or critiques of extreme claims of gender ideologues, especially those touting the benefits of what’s called “affirmative care” (adolescent dysphoria—> doctor on board prescribes puberty blockers almost immediately—> hormones, surgery, and gender transition). The recent history of the field, documented in the first paper below, involves repeated attempts to allow questionable claims to stand in the literature. Two examples of this are the unsupported claim that affirmative care prevents suicide, and the release of the paper by Johanna Olson-Kennedy et al, which was held back because the results (puberty blockers did not improve mental health) were not in line with what author thought gender activists wanted to see.  The paper by Cohn below (click to read), summarizes many of these forms of censorship or distortion.

Here’s the abstract:

The integrity of the gender medicine research literature has been compromised, not only by censorship of correct articles, but also by censorship of critiques of articles with unsupported (for instance exaggerated), misleading or erroneous statements. Many such statements concern the evidence base, which can be evaluated rigorously using a key component of evidence-based medicine, systematic reviews of the evidence. These reviews currently find there is limited to very little confidence that estimates of benefit from (and sometimes harm from) medical gender intervention, that is, puberty blockers, hormones and/or surgeries, are likely to match true outcomes. Several medical societies and articles in medical journals have been claiming otherwise, misrepresenting the evidence base as a whole and/or relying upon unsupported or non-representative individual study findings or conclusions. For example, high likelihood of benefit and low risk of adverse outcomes from medical gender interventions are often claimed, while less invasive alternative treatment options are either omitted or mischaracterized. Other unsupported, erroneous or misleading statements occur when studies minimize or omit mention of significant limitations, or report findings or conclusions not supported by their own data; these are then sometimes quoted by others as well. In addition, correctly reported studies are sometimes misrepresented. Critiques which attempt to rectify such statements are frequently rejected. Some examples are presented here. Such rejections have stifled scientific debate, interfering with the continual scrutiny and cross checks needed to maintain accuracy in the research literature. Currently, erroneous and unsupported statements circulate and repeat between journals and medical society guidelines and statements, misinforming researchers, clinicians, patients and the general public.

If you want a three-page summary of the paper above, which you really should read in toto if you’re interested in gender medicine, read the article below (click headline to read) gives a terse summary.

I can’t summarize the first paper in detail, and you really should read it for yourself. I can, however, give a few quotes from Linehan’s summary on his Substack, which is a bit choppy (quotes indented below). Linehan begins by citing the paper above:

‘Censorship of Essential Debate in Gender Medicine Research’ has the dullest possible title for what it reveals. In yet another example of trans ideology destroying everything it touches, the most prestigious journals in medicine are refusing to publish corrections to papers that contain demonstrably false claims about gender medicine.

The author, J. Cohn, didn’t set out to write about censorship. She tried to correct errors in published papers. When that didn’t work, she described what happened. She found that multiple systematic reviews (the gold standard in evidence-based medicine) have found low or very low-certainty evidence for the benefits of medical gender interventions. This includes puberty blockers, hormones, and surgery. ‘Low certainty’ means there’s limited confidence the estimated effects will match what actually happens to patients.

The Cass Review, published in 2024, found the evidence for paediatric interventions “remarkably weak.” Several other systematic reviews found the same for patients under 21 and under 26.

None have found that these interventions reduce suicide risk.

Meanwhile, major medical journals keep publishing papers claiming the opposite.

Papers in JAMA, the New England Journal of Medicine, and Pediatrics have variously claimed that gender-affirming medical interventions are:

  • “Widely recognised as essential, evidence based, and often lifesaving”
  • Known to “clearly improve health outcomes”
  • Associated with “demonstrated health and well-being benefits”
  • Linked to regret rates “less than 1%” or “exceedingly rare”

The regret claim is particularly bold given that the studies cited have major flaws. The often-quoted Bustos review included 27 studies, of which 23 had moderate-to-high risk of bias. All included studies suffered from premature follow-up, significant loss to follow-up, or both.

And one more bit:

Medical guidelines are supposed to work like this: researchers conduct systematic reviews of all available evidence, assess its quality, and make recommendations that match the strength of that evidence. Strong evidence gets strong recommendations. Weak evidence gets weak recommendations or no recommendation at all.

That’s not what happened here.

The American Academy of Pediatrics policy statement recommending gender-affirming care wasn’t based on systematic reviews. A subsequent analysis found its cited references “repeatedly said the very opposite of what AAP attributed to them.”

The Endocrine Society guidelines make strong recommendations based on evidence they themselves rate as low or very low certainty. They don’t explain why.

WPATH commissioned systematic reviews, then interfered with them. After publication, they dropped all but one minimum age recommendation (for phalloplasty) under pressure from the Biden administration and the AAP.

This whole field is rife with a form of advocacy so extreme that researchers not only hesitate to publish results that go against the preferred ideological narrative, but also repeatedly distort studies that criticize affirmative care.

This is not the way science is supposed to be done, but it’s what happens when ideology begins to erode the norms of science. This of course is not new: it’s what happened with the Lysenko affair in Soviet Russia (documented in our paper, Jussim et al.), when ideological distortion (and outright cheating) ultimately killed millions of people.  Nobody’s claiming that kind of toll for gender medicine, but there is still a palpable human cost to sloppy research.

h/t: Joolz

Videos: Dawkins on sex differences; Neil deGrasse Tyson on sport and sex

October 13, 2025 • 9:30 am

The first article in the new anthology The War on Science (compiled, edited, and with an introduction by Lawrence Krauss) is a piece by Richard Dawkins called “Scientific truth stands above human feelings and politics.”  It’s basically a two-part essay on how ideology has distorted science, with the first part being about Trofim Lysenko’s distortion of Russian genetics under Stalin, and the second bit being about sex and gender, concentrating on the biological nature of sex. In the UnHerd interview below, Richard dilates on the part about sex and gender, but concentrating on the evolutionary biology of sex.  As I’ve said, the book has been attacked by miscreants—many of whom hadn’t read it, but damned it nonetheless because some of the authors were deemed politically unpalatable and because the topic was how the left has damaged science. (“We should”, say these miscreants, “have written only about the damage that Trump and his minions have done to science.”)

Dawkins is one of the people who has brought opprobrium down on the book, because, after all, he’s an “old white man”, a member of the most oppressive group at all. But his age, sex, and race are irrelevant to his essay, which is one of the very best in the anthology.  In his characteristically clear and eloquent writing, he explains what he calls the “universal biological definition of sex” (“UBD”): the now-familiar claim that biological sex is based on relative gamete size. This definition leads ineluctably to the view that sex is binary: there are two and only two forms of gametes in a given species. He underlines something that I’ve also emphasized: the UBD is not only ubiquitous, applying in binary form in all animals and vascular plants, but is also explanatory: the sex binary is the only concept of sex that can explain, usually via sexual selection, a number of phenomena that puzzled biologists before Darwin proposed this form of selection in 1871.

In the UnHerd video discussion with Freddie Sayers shown below, Richard runs through 14 of these phenomena, making an airtight case for the utility of the UBD.  He also takes up issues raised by the Miscreants to try to show that sex is a spectrum: the sequential switching of sex by clownfish and wrasses (they’re still male or female), the presence of intersex individuals, whose frequency is very low and no damaging to a binary view, and the fact that male seahorses can get “pregnant,” holding fertilized eggs in a pouch until they hatch (notice I say “male seahorses”, for these individual still produce only small, mobile gametes).

Because advocates of the “spectrum of sex” view are ideologues, who hold their position simply because they think the sex spectrum buttresses transsexual and nonbinary individuals, Richard’s talk here, or his essay in the book, won’t convince these opponents. (By the way, these people never tell us how we can define the sexes given that “sex is complicated.)  But if you’re open minded, have a listen, or better yet, buy the book, as the essay has a lot more than does the interview below. The universal and explanatory advantages of the UBD make it far superior to any other concept of biological sex.

h/t: Luke

In the short (4-minute) clip below from The Rubin Report, astrophysicist and science popularizer Neil deGrasse Tyson takes another point of view. Interviewed by Michael Shermer, Tyson gets all worked up on the topic of sports, finding it deeply weird that we split males and females when it comes to athletic competition. Two women, broadcaster Sage Steele and former swimmer Riley Gaines, weigh in on Tyson’s confusion.

Finally, below is the full interview of Tyson by Shermer. It’s on sex and race, and I’ve started it when they begin discussing sex (31:15).  You can see that Tyson apparently thinks from his astrophysical background that nature is structured against binaries, which he sees to consider an argument for the continuum of sex. He seems to deny, in fact, that there’s any value in discussing biological sex, and that gender is what’s important. (Remember Tyson’s famous “today I feel 80% female and 20% male” statement?)  As far as sports is concerned, Tyson suggest dividing sports up in to “hormone categories”, so people compete against others having with similar hormone ratios. (That’s problematic for several reasons, not the least being that people who take hormone supplements, like trans-identified males, may still have a strength advantage over biological women having a similar hormone titer, because the advantage is already there at puberty,  before most takes testosterone).

Then, pressed by Shermer, Tyson says that maybe we should use a combination of body weight and hormone titer. It’s a mess, which becomes simplified if you have three categories: “bioloigcal [natal] female,” “biological [natal] male,” and “other”. Alternatively, you might stipulate that anyone who is not clearly a biological female compete in the men’s class. (That too has problems, like a higher risk of injury for trans-identified females in competitive sports.)

At any rate, this discussion is really an add-on to the Dawkins video above, so listen if you have the time.