Sex in humans may not be binary, but it’s surely bimodal

October 28, 2018 • 9:30 am

There seems to be repeated confusion, willful or otherwise, about the nature of sex (here I’m talking about biological sex, not gender, which is one’s perceived identity). I’m fine with anyone calling themselves whatever they want, except that it may not be so easy for sports divided into “men’s” and “women’s” events (but I’m glad I don’t have to adjudicate that issue).

But with sex, well, biological sex in our species, and most other sexually-reproducing animals, does fall into two classes, male and female. The Oxford English dictionary defines “male” in biological terms as

That which belongs to the sex which can produce offspring only by fertilization of the opposite sex (contrasted with female); characteristic of or relating to this sex.


Of the reproductive organs of an animal or plant: characteristic of the males of a species; producing gametes (such as spermatozoa) that can fertilize female gametes (ova). Also: designating such gametes, which are usually smaller and more motile than the corresponding female gametes.

Female” is defined similarly with respect to fertilization and gamete size:

A person of the sex that can bear offspring; a woman or a girl.


Of the reproductive organs of an animal or plant: characteristic of the females of a species; producing gametes (ova) that can develop into a new individual, usually (but not always) after fertilization by a male gamete (as a spermatozoon). Also: designating such gametes, which are usually larger and less motile than the corresponding male gametes.

Now of course you can find some exceptions among some species. In seahorses, for instance, males can “bear offspring” because they raise the fertilized eggs in their pouch, but nevertheless they still produce sperm.  But in humans it’s rarely doubtful whether an individual is a male or a female. Males have a chromosomal constitution XY, produce small gametes that fertilize the large eggs of females, and have male genitalia (penises). Females produce fewer but larger gametes, are XX in chromosomal constitution, and have female genitalia (vaginas).

Of course there are some exceptions to all of these. We have humans with chromosomal constitutions XXY and XO; we have developmental intersexes that have characteristics of both male and female, we have females and males with all the traits above but which are sterile and so can’t produce eggs or sperm, and so on.

The point is that these exceptions are rare. I don’t know the figures for males and females that fit neatly into the classes I’ve given above, but I’d guess it would be about 98% of humanity; the Intersex Society, lumping chromosomal and developmental exceptions together, gets a frequency of non-binaries of about 1-2% (Fausto-Sterling gave roughly the same figure in 2001). So yes, sex isn’t truly binary in that every individual can’t be unambiguously slotted into either male or female—but the vast majority can.

What this means is that if you do a plot of sex versus frequency in which you combine all traits that define “males” (above) at one end and those defining females at the other, and then plot the frequency on the Y-axis, you’ll get a plot with two distinct and widely-separated peaks, with a valley containing some intermediates (intersexes and the like) between them. This is what I mean by the bimodality of sex. And there’s a reason for it: having two sexes is the result of evolution in our ancestors. (I won’t go into why, nor do we fully understand the selective pressures). Let me add that I’m talking about biological sex here and not gay behavior, so that I am counting male homosexuals as males because they have the physiological and chromosomal features of males, even if they are sexually attracted to males, and the converse for lesbians.

Yet Anne Fausto-Sterling, an emeritus professor of biology and gender studies at Brown university, conflates the issues of sex and gender in her op-ed piece in the New York Times (below), implying that because sex is not “binary” (i.e., there are some exceptions), that it is not bimodal. Now she doesn’t use the word “bimodal”, but the implication here is that somehow science has decided that there are more than two biological sexes, and implying that there is just two is somehow damaging to those individuals who are intermediate. (Again, I’m not referring to transsexuals here, many of whom are born having one distinct biological sex but decide, as a matter of gender preference, that they’re members of the other, intermediate, or are members of some unusual gender.) Her article, as you’ll see from contrasting the title with the last paragraph, conflates sex and gender, and I think that’s deliberate. But it’s confusing and mistaken.

Click on the screenshot to read the article:

You can see by the subtitle that she is discussing biological “complexity”. And yes, there’s complexity if you look at the 1-2% of people who are not binary but intermediate between “male” and “female.” But throughout the article, Fausto-Sterling concentrates on these exceptions, managing to convey the message that they are so common that we really shouldn’t think that the human population falls nearly into two sexes—that biological sex isn’t even close to being binary. In fact, in the entire article, Fausto-Sterling doesn’t mention the frequency of these exceptions, which we need to consider if we want to know what we mean when we claim that “there aren’t two biological sexes in humans”.

Note that Fausto-Sterling’s piece is a biological response to a political decision: Trump’s Department of Health and Human Service’s desire to legally define sex as “a person’s status as male or female based on immutable biological traits identifiable by or before birth.” One can object to that definition on three grounds. The first is that not every single person will fall into these categories no matter which “immutable biological trait” you use.

The second is that it’s completely worthless because sex, like gender, is a social construct. Now the latter seems silly to those who know anything about biology, but the idea that sex itself is a social construct is increasingly common (see my critique of one such claim here).

The third is that the definition was made to disenfranchise, punish, or demonize transsexuals (many of whom were born fully male or female), and has no useful social value. I don’t see what social value it does have, so on first principles I’m not behind it.

But back to the biology. Fausto-Sterling does state the truth at the outset:

It has long been known that there is no single biological measure that unassailably places each and every human into one of two categories — male or female.

But then she goes into the many layers of complexity, to wit:

  • Chromosomal: some individuals are XXY, XXY, XO, and so on.
  • Developmental  issues that produce non-“binary morphological individuals based on hormones or other non-genetic factors.
  • The perception of “genital sex” by adults affects how adults socialize the children. That, however, is a social issue that is the outcome of “nonbinary” biological factors, and doesn’t belong on Fausto-Sterling’s list.
  • “Brain sex”: Brain cells, stimulated themselves by fetal hormones, can also produce intermediate sexual morphology in the body. But this is also a developmental issue, falling under the second point above.

And yes, these exceptions make unambiguous classification of some individuals based on biological traits a dicey affair. But not often: it works, I’d guess, at least 98% of the time. So I think Fausto-Sterling is exaggerating a bit when she says this:

By birth, then, a baby has five layers of sex. But as with chromosomal sex, each subsequent layer does not always become strictly binary. Furthermore, the layers can conflict with one another, with one being binary and another not: An XX baby can be born with a penis, an XY person may have a vagina, and so on. These kinds of inconsistencies throw a monkey wrench into any plan to assign sex as male or female, categorically and in perpetuity, just by looking at a newborn’s private parts.

The question is how much damage that monkey wrench really does. Not much, I’d say.  And for most purposes, including sports, the exceptions are few. Where we run into problems, by and large, is where “non-binary” people want to compete in sports as females, though having the upper-body strength of males. Many people, including women athletes, see that as unfair. I won’t enter that controversy, as I don’t know how to resolve it. (I’ve suggested a third category in addition to “male” and “female”, but I’m not wedded to that solution.)

And the bit below is a tad exaggerated, because the “wide” variation isn’t all that wide. The disputes arise because the problems in sports come precisely from those few individuals whose sex is ambiguous:

Dr. Money called these layers pubertal hormonal sex and pubertal morphological sex. But these, too, may vary widely beyond a two-category classification. This fact is the source of continuing disputes about how to decide who can legitimately compete in all-female international sports events.

Fausto-Sterling’s purpose is ideological, and adding information about how sex is determined doesn’t change the strong bimodality of sex, so this bit is obfuscation:

There has been a lot of new scientific research on this topic since the 1950s. But those looking to biology for an easy-to-administer definition of sex and gender can derive little comfort from the most important of these findings. For example, we now know that rather than developing under the direction of a single gene, the fetal embryonic testes or ovaries develop under the direction of opposing gene networks, one of which represses male development while stimulating female differentiation and the other of which does the opposite. What matters, then, is not the presence or absence of a particular gene but the balance of power among gene networks acting together or in a particular sequence. This undermines the possibility of using a simple genetic test to determine “true” sex.

In fact, what matters is how often the outcome of these opposing networks yields a binary result: male or female. Whether the network is the presence or absence of a particular gene or of several genes is completely irrelevant. And the answer to how often the process yields a binary result is this: almost all of the time. Whatever “undermining” there is, it’s not a serious undermining.

Let me reiterate what I’m trying to say here, because I think Fausto-Sterling’s essay is motivated by good will and is not blatantly wrong, just misleading.

1.) Human sex is not absolutely binary because there are exceptions no matter how you define “male” and “female”.

2.) Those exceptions, however, are rare, so considering most individuals, sex is binary. And for the population of humans, sex is strongly bimodal: most people, no matter whether you define sex using chromosomes or morphology or gamete structure, fit into the classes of either “male” or “female.”

3.) I agree with Fausto-Sterling that it’s unwise to try to impose an absolute binary system on all human beings. That’s hurtful to intermediate or non-binary individuals, who, as I’ve always maintained, should be treated with respect, dignity, and as much accommodation as is compatible with social well-being.  But we simply cannot maintain that sex is a social construct like gender. And Fausto-Sterling’s last paragraph, despite the title of her piece, conflates sex and gender (my emphasis below):

The policy change proposed by the Department of Health and Human Services marches backward in time. It flies in the face of scientific consensus about sex and gender, and it imperils the freedom of people to live their lives in a way that fits their sex and gender as these develop throughout each individual life cycle.

I haven’t pondered the HHS definition, but I suspect it is aimed at transsexuals, and if it is then it’s likely nefarious. But we shouldn’t pretend that sex is a continuum or not bimodal simply to justify social conclusions. Fausto-Sterling walks a fine line between sex and gender, and crosses it at the end.

We can still say that someone who has surgery to convert from a male to a female gender was born a biological male, and what does it matter, except to either officials of the Olympics (who do face a big issue) or Republicans who are bigoted? We should take our stand on gender from a liberal morality, but we should not pretend that sex itself is a continuum, for that depends on a distortion of biological data. And I’m not saying that Fausto-Sterling pretends that sex is a continuum, but neither does she emphasize the strong nature of its bimodality: a bimodality that is of no consequence when it comes to gender issues. Gender may be a social construct, but sex is not.

4.) To reiterate: we shouldn’t get social “oughts” from biological “is”s, nor inappropriately wrangle science into supporting claims about morality and ethics. There are sufficient reasons to oppose the Trump regime’s proposal without obfuscating or spinning the facts to try to prop up your position.


113 thoughts on “Sex in humans may not be binary, but it’s surely bimodal

  1. “Yet Anne Fausto-Sterling, an emeritus professor of biology and gender studies at Brown university, conflates the issues of sex and gender in her op-ed piece in the New York Times (below), implying that because sex is not ‘binary’ (i.e., there are some exceptions), that it is not bimodal. Now she doesn’t use the word ‘bimodal’, but the implication here is that somehow science has decided that there are more than two biological sexes, and implying that there is just two is somehow damaging to those individuals who are intermediate.”

    Oh boy am I sick of hearing this argument. Some people are born without fingers, yet this does not mean that humans cannot be defined as not having ten fingers. People who are born without ten fingers are abnormal; something went wrong with their development. We cannot convince society or intersex people that being intersex is not a developmental anomaly outside the normal range of the human body’s construction, and we shouldn’t try to convince anybody of that because it’s not true. We should simply treat such people the same way we treat people born with other physical handicaps and abnormalities: with simple respect, just like everyone else. When people like Ms. Fausto-Sterling constantly chide everyone for not agreeing with their view of things, it only annoys people and shines a constant spotlight on a group that I imagine largely would like to go on living their lives like everyone else, rather than being used as tools for activism.

    Ms. Fausto-Sterling and others like her use intersex people as a tool for their activism toward abolishing the idea of sex/making sex something that is “fluid” and/or has many different categories. There are only two sexes: male and female.

    1. ” Some people are born without fingers, yet this does not mean that humans cannot be defined as not having ten fingers.”

      Sorry, this should say “does not mean humans cannot be defined as having ten fingers.” I meant to say that humans can be defined as having/are supposed to have ten fingers.

    2. In the early days of the internet I noticed a surprising number of people had difficulty understanding the concept of the generalization-that what your’re saying is true in the majority of circumstances but not not necessarily true in all of them. They throw about the phrase, “That’s just a generalization!” as if it was a counter argument. You could say, “In general, humans have brown eyes.” and you’d get a dozen people responding with “Nuh-uh. I have blue eyes. Are you saying I’m not human!”
      Somehow I think this has metastasized into nothing is true in general.

    3. I think an important point of emphasis that’s often neglected is that these arguments always commit the fallacy of focusing on particular instantiations and neglect the causal factors underlying sex. In the genome, the sexes are discrete categories, and subject to natural selection. The sexes evolve in different directions. Sometimes they compete in evolutionary arms races. This ought to imply that the sexes have some real existence outside of gene expressions in particular cases.

  2. Very nicely and clearly argued. But in the penultimate paragraph that should be “We can still say that someone…” (not ‘… somehow…’).

  3. ‘Intersex’ is a misnomer. Nobody is midway between male and female. There’s no gamete which has the properties of both a sperm and an ova. We don’t talk about ‘egg motility’, sperm do not wait passively for ova to seek them out, and fresh ova are not generated throughout the life of an intersex person the way sperm are for men.

    XXY, XXX, and the rest aren’t sexes. They are trisomies. XXY is male, XYY is male, XXX is female, XO is female. It’s the presence or absence of the Y chromosome which determines sex. Many of these conditions effect fertility but being infertile doesn’t mean you belong to a third, intermediary sex. If we define sex in terms of reproductive role there can be no infertile sex by definition.

    In very rare cases the SRY gene might be inactive resulting in a female phenotype but they are still chromosomally male.

      1. And then there’s androgen insensitivity syndrome (AIS): people with XY who don’t metabolise testosterone, and are often unaware until being medically tested in adulthood that they are anything but female.

        I think intersex is a useful term for a whole bundle of confusing conditions like this. Perhaps a better word could have been chosen, it’s not meant to indicate half-way, but well english has many strange words.

        (If I remember right, AIS people are allowed to compete as women in the olympics, and this seems fair.)

        1. I think it’s a terrible term that gives the impression intersex people are some midpoint between male and female.

          Some of the conditions lumped in with ‘intersex’ are ridiculous. How is a boy with aposthia (being born without a foreskin) not 100% male?

          1. Oh I didn’t know they did that, I’m surprised. The conditions I knew about were all more along the lines of ticking some boxes in the M column and some in the F, for which it struck me as a fairly neutral term. Is there an existing term for a more narrow category like this?

      1. My thought too. I always assumed it came from the Latin word, and therefore simply means, “between”.

  4. Alsi, intersex groups have repeatedly asked not to be dragged into what is essentially an argument about transgender. Somebody changing their pronouns so they can thrash women at sport isn’t intersex. Nor is a rapist who wants access to a women’s prison.

    Nobody questioned the sex binary when the issue was simply intersex people; it has only come to prominence through transactivism. It’s an attempt to blind people with science.

    1. Doctors do not assign sex. They observe it.

      They may incorrectly observe it if the genitalia are malformed and their observation may need amending at a later date but your sex is determined at conception, not at birth, and not by a doctor.

      If you have some X chromosome related condition it is going to develop in the womb irrespective of any observation your doctor might make.

      1. Is there not a blank for “sex” on a birth certificate that the doctor (or someone else at the hospital or wherever) is required to fill out? I believe there is on my birth certificate but I’m old.

    2. Could the parents not tell?

      In somewhere between one and ten of a thousand live births, the midwives and/ or doctors present cannot themselves confidently “tell” the appropriate classification of the newborn “on sight”. Depending on workloads, that will mean that a full-time professional (midwife/ doctor/ meh) will be seeing on the order of one ambiguous case every two to four years. Uncommon, but far from unknown. In fact, I’d go as far as saying that a full time professional in that industry who hasn’t seen a case of ambiguous external genitalia is really still in the “learning the ropes” stage of their professional development. After the first decade on the job, it’d be “oh rude words about gonads! ; yet more paperwork trouble”.
      By contrast, the most prolific birth-giver on record (pick whichever you believe from this list; anywhere from the mid-30s to the mid-60s) would have had a less than 1 in 3 chance of seeing their first case of ambiguous external genitalia.

  5. “Gender” was originally a grammatical concept that referred to the tendency of (some) languages to organize nouns into classes. In some languages (e.g. French) these classes overlap with the physical sex of the person they refer to.

    Gender was later used by feminists to refer to a socially constructed system that oppresses and controls females, and they argued for its abolishment. Then it was extended to describe identity and the range of expression of one’s sex (ranging between ‘masculine’ and ‘feminine’ norms).

    Then gender became a euphemism for sex (I remember watching a TV show in the early 90s in which a woman wanted to know the “gender” of her baby, which I found a bit odd), to the point now where people seem to use the terms interchangeably. So before, someone who wanted to take on the characteristics of the opposite sex was “transsexual”.

    Now it seems that we have gotten to the point where one can identify as a woman or a man (or neither) without making any effort to take on the characteristics of that sex, and that this identity overrides physical sex. I’m happy to treat someone however they want to be treated and I think that we need to safeguard the rights of gender non-conforming people but the idea that this negates the fact of sexual binarity goes against science and rational thought.

    1. “Gender” was originally a grammatical concept that referred to the tendency of (some) languages to organize nouns into classes. In some languages (e.g. French) these classes overlap with the physical sex of the person they refer to.

      I really should go back into learning German. Where, of course, there are three grammatical genders, including “neuter”.
      Anyone got an advance on three? I’d be pretty surprised it three was the maximum for grammatical “genders”.

        1. Wolof does not have gendered pronouns at all, but oddly they have not achieved equality between the sexes, and I wouldn’t try to be trans there.

      1. Neither Turkish nor Chinese has gender.

        Of course neither Turkish nor Chinese society are patriarchal./sarc

  6. I can’t agree that gender is a social construct. I don’t even agree that the term gender should be applied to people, animals or plants. That is a misuse of the term. People are either male or female. Wanting to be something other than what you are does not make you something you are not.

    I fon’t know what yo do with the few that are not comfortable with what they are or are biological intermediate. Education that those people exist is s start.

    1. I can’t agree that gender is a social construct.

      It is certainly not *purely* a social construct. The gender identities do have a lot of biology underpinning them.

      1. There is currently disagreement about whether gender studies or gender has anything to do with biology or is a study of behavior.

          1. Behavior is a result of DNA and environment, starting before birth. That gets complicated. Maybe our host will write a post on that one day.

    2. I think you may be muddling terms a bit. I think you are mixing up sex and gender. As I see it (I agree with Dr PCC(e)) biological sex is bimodal in humans and is not a social construct. It is what it is.

      How we behave in our sex roles, is gender and it is constructed partly by social mores. We behave in ways society assigns to sex roles and most of us adhere to the roles most often associated with our biology. But there is a great deal of variance to those roles and we can switch from one to another (if we’re allowed to).

      Then there’s sexuality and that is almost entirely constructed. And often weird.

      1. I don’t agree that gender should be applied irrespective of biology.
        That just virtually does away with the meaning of the term.

  7. I believe that people should be able to live in whatever manner they choose without hassle-provided they’re not harming anybody. You’re a man who wants to wear a dress and make-up? Knock yourself out. I’ll play along and refer to you as “she” and “her”, because it costs me nothing to do so. I don’t care which toilet or locker room you use. Where you lose me is when you insist that I accept as real that you were born a woman and have always been one, that biological sex is a matter of social convention, that biologist who deny this are bigoted “garbage humans” who need to lose their jobs, and that children who play dress-up need to be on hormone replacement therapy.

    1. “I don’t care which toilet or locker room you use.”
      The two of us, as men, may not care all that much. Many women may however object (for good reason) when men in dresses show up in their locker rooms.

    2. And yet when I walk into a restroom or a sauna and encounter an exposed penis, my first response is not “oh, it costs me nothing;” my first response is “who is this man and why should I assume that I’’m not in danger?”

      The solution offered by proponents of gender-identity-over-everything is that I, as a female human who does not wish to be exposed to the penises of strangers, must relinquish my right to public accommodations and stay at home, basically a secular and oh so progressive version of purdah.

  8. Yeah, sex might be bimodal. Hell, it can even be bipedal — unless you’re Baptist, then it looks too much like dancin’.


  9. I’ve suggested a third category in addition to “male” and “female”, but I’m not wedded to that solution.

    The problem is that there would not be enough competitors in the third category to make any sensible sport.

    I think we have to go to “open” and “narrowly-defined female”.

    1. This is precisely what the special olympics are for.

      To try to have enough competitors, in every sport they aggregate with a wide variety of birth abnormalities, and of injuries, to try to make a series of fairly fair competitions.

      It’s not prefect, but it’s pretty good. And gets a lot of support relative to the size of the populations being served, which is great.

      1. No transwoman is going to accept a third option in sport, or anywhere else for that matter.

        It’s all about validating their gender identity. Anything less than full access to all women’s spaces is an acknowledgement of difference.

        1. How about only two options; “Open” where all can compete and “women” – only those who meet a constrained definition of biology can compete. Even here there will be exceptions, but most of the controversial ones are dealt with by the “Open” division.

          It is a very gnarly knot to untie. I do not envy sports authorities dealing with this issue.

          1. Feminist Melissa McEwen once supported eliminating sex segregated sports and instead having multiple “weight classes”. It’s one of those concepts that looks good on paper, but in reality would spell doom for women in professional sports. So, why do I want to see it happen then?

            1. This is such a thorny issue because sport doesn’t just rely on competition – after all what really is the point of running around kicking balls?

              Even the “open” category I suggest above is not without serious flaws. One thing that is clear with the huge increase in women in sport is that although they are not as fast or strong in magnitude as men, their level of competition is just as good.

              One thing that would not be good for women’s sport would be to let them compete against men. Not because I think they wouldn’t be good at it – they won’t win many against the world’s best men but there is an enormous number of competitions below the elite level where they CAN win against men. The problem I see is that if women are allowed to compete against men in Open divisions it could wind up with the Women’s division lacking top talent and, ultimately, becoming second class. The NIT tournament vs NCAA. Much rather see Women’s division as one of the two for humans.

              1. Im would suggest that, in most physical sports, the women would have to go a long way down below elite level to be competitive. For example, in tennis, no woman would ever qualify for the “open” category of any major tournament.

                Serena Williams would be less well known than Karsten Braasch.

              2. “Not because I think they wouldn’t be good at it – they won’t win many against the world’s best men but there is an enormous number of competitions below the elite level where they CAN win against men.”

                Unfortunately, this isn’t the case either. The best women’s Olympic ice hockey team in the world lost to high school boys teams back in 2014. The US Women’s Soccer team (by far the best women’s soccer team in the world at the time) lost to an under-15 boys’ academy team.

              3. Braasch was ranked 203rd at the time, played a round of golf and had a couple of beers before that exhibition. And he said he played like someone “ranked 600th” just to keep things “fun.”

                According to Wikipedia, a journalist described Braasch as “a man whose training regime centered around a pack of cigarettes and more than a couple bottles of ice cold lager.” Makes one wonder how good he would have been if he actually tried, but I imagine there are many such stories when you get to rankings that low: people who have tons of talent, but just don’t want to put in the work to make it big.

            2. I wonder whether Mrs McEwen would reconsider after a couple of female boxers and mixed martial artists have been killed in the ring by men who are in the same weight class, but still 50% stronger.
              Let’s face it: the demands for acceptance by trans activists will, if granted, dismantle many of the protections that women currently enjoy (often for good reasons).

          2. Indeed, the trans-women will fight this battle pretty hard. But the are deluded if they think the near-equal status which women’s sports have achieved, based on representing 50% of the population, will long survive their victory.

            One precedent for open and restricted competitions comes from boxing, where everything below heavyweight has a hard rule. This is absolutely the way that we ought to go. Although I agree that it will be harder to write these rules, they will require more than a bathroom scale to enforce.

            1. Those rules like in boxing already exist. When I was racing bicycles I was a cat 3 or 4 racer – I could not enter Pro or Cat 1&2 races. Just so, when I ran road races, I was pretty good, but not an elite, so I could not start in the first flights. Now my son plays on a Select league soccer team – they don’t play against Premier teams

              Sports can handle differences in skills and abilities that are specific to the sport. Since many of those are influenced by the Y chromosome, the largest difference to accommodate are between biological males and females. Sport can handle this.

              What we’re asking them to do is deal with differences in philosophy, ethics and perception. That’s a hard thing to be fair about.

              1. But is there a Cat 3 trophy? I thought that was a little different, basically just accommodating lots of riders in limited road space. (And the prize for winning 2nd-league soccer is promotion to the 1st league.)

                The special olympics does give medals for the top of each class. And this is obviously a little selective, as the worst guy who was included in the 2nd class would often win the 3rd class… but there’s no way around that. The participants still train damn hard, and the medals have some glory.

                I think M/F (or Open/F) is actually more like boxing. An acceptable classification rule would apply to all sports and put 49% of the general population (geriatrics included) into the F category.

              2. “But is there a Cat 3 trophy?”

                Yes, of course. Or sometimes a pizza (some of the races I entered were pretty small).

              3. I’m completely OK with a new rule that the fastest self-declared not-a-man in each open-class olympic even should be bought a pizza 🙂

                For the first self-declared not-a-man to enter a heavyweight boxing ring, I’ll buy the pizza myself.

        2. “No transwoman is going to accept a third option in sport, or anywhere else for that matter.”

          Transwomen, of course, have a hive mind, with none of them having an opinion of their own.

        3. I remember the case of Renée Richards. A professional male player who transitioned and wanted to play in the women’s circuit. I remember being worried at the time that it would be an unfair competition. She was initially barred but then a judge ruled she could not be discriminated against. She played in the US Open but it turned out that she could not beat the best women. Rather a sad situation. She was demanding respect, yet she was in danger of being unfair to other women.

  10. Presumably Dr Fausto-Sterling would refuse to recognize the existence of day and night, on the grounds that at twilight and dawn, we’re not clearly in one state or another. Which of course she is entitled to do, but it is likely to make her quite dangerous as a driver.

  11. There’s another sense in which sex is absolutely binary, not just strongly bimodal: every single human has a mother and a father. Looking backwards it’s 100% clear, looking forward it’s muddled by abnormalities.

    (With a possible footnote about that one case where they implanted one woman’s egg’s nucleus into another’s cell to avoid some mitochondrial error. That kid, if it was born yet, and depending on your definitions, may have in some sense two mothers.)

    1. I think you can have two mothers in the sense that an embryo could have the mitochondria of a third ‘parent’ but this would only be possible with IVF. There’s no way of doing this the fun way.

      1. Right, and looking it up, the first such baby in history was born last year, 2017. Whether it honestly has two mothers is a matter of definition (and clickbait-ing). And what we will do in the future remains to be seen. But the past is 100% crystal clear, all the way back to Adam & Eve.

      2. I recently read that a small, but not insignificant percentage of turkeys (Meleagris gallopavo) reproduce parthenogenically – their offspring have only one mother.

        Parthenogenicity occurs in humans too, but the developing egg winds up as a tumor -fetaform teratomas. Tumors! Which, in my darker days, I sometimes think that’s all we really are – tumors that have metastasized outside our mothers.

        1. derp; “…their offspring have only one mother.” Well, that’s not so uncommon, is it? After all, I only had one mother. I bet you did too.

          *sigh* I meant; “their offspring have only one parent.”

  12. In 2016, Kate Hall was the state champ in the 100m Connecticut’s state track and field championship.

    In 2017, Andraya Yearwood, a biological male, beat her to win the girl’s CT state 100m track title.

    This year, Terry Miller, who ran the winter season as a boy, switched over to compete with the girls in the Spring and beat Yearwood to win the title.

    The biological males went 1-2.

    The biological females had to fight it out for third.

    The videos are on YouTube if you care to look them up.

    This has become comical lunacy.

    PS: Two weeks ago, the same happened at the 2018 UCI Masters Track Cycling World Championships. Biological male took the title.

    1. Sports have classes or groups to provide a level playing field for the members of that class. Nobody should be able to arbitrarily shift themselves into a class where they have an inherent advantage over everybody else. There is too much self-interest involved. If it isn’t blatant cheating, it’s pretty close to it.

      It may be hard on M-to-F transitioners to say ‘you compete in your original class (gender) or not at all’ but the interests of the many have to outweigh the interests of the few.


  13. In Quillete, Deborah Soh writes an interesting essay that touches on a topic that I know is on the mind of some gays and lesbian, maybe not that many but enough: That they themselves as children were gender dysphoric and grew up to be gay/lesbian.

    But in the new dispensation, many of us would have been adviced, pressured to undergo puberty blockers, cutting of genitals, etc….and we would have been miserable as the vast majority are perfectly happy as gay males and lesbians of the sex we were born.

    I wonder if in several years we won’t see many law suits against school districts where counselors adviced/pressured gender dysphoric children to undergoing highly invasive physical treatments.

  14. My little Nissan Versa automobile is very concerned that the evil Republican government is forcing on it the identity specified by its VIN. This identifies it as a Japanese-made Nissan sub-compact, whereas in its heart of hearts it feels it ought to be a Cadillac Escalade. On weekdays, that is. On weekends, it thinks of itself as a Jeep Cherokee.

    1. When the Kurzweilian singularity arrives, and your little Nissan gains consciousness, I’ll be the first to call it “Caddy” (though it still won’t be able to turn the quarter mile in anything less than hourglass time).

  15. I haven’t pondered the HHS definition, but I suspect it is aimed at transsexuals …

    My sense of it is that this is the ongoing rearguard action reactionaries are fighting against gay rights, a battle they’ve lost (as an earlier generation of reactionaries lost the battle against miscegenation) probably for good (depending upon how frisky the new conservative SCOTUS majority feels about abandoning precedent), in their perfervid effort to draw the line before men lie with beasts and lions with lambs and dogs and cats start living together in a world beset by biblical abominations.

  16. “but we should not pretend that sex itself is a continuum”

    I’m a bit confused over the use of the term “continuum”. I think by the dictionary definition sex should indeed be called a continuum even if bimodal:

    “a continuous sequence in which adjacent elements are not perceptibly different from each other, although the extremes are quite distinct”

    To me this sounds like a continuum describes small changes across the spectrum which does not preclude bimodality. In a bimodal population the rate of change may vary. So, I’d call sex a bimodal continuum. I could be wrnog.

    1. I guess we’re all merrily abusing the terminology here, using continuum to mean “like the rainbow” and bimodal to mean “two giant lumps, and 1% which isn’t obviously part of either”.

      There’s not really a continuum from male to female along which interesex & trans conditions can be usefully ordered. (Unless you go by page numbers in the DSM or something.) There are lots of different pieces of information, and we’re discussing high-dimensional clustering.

  17. “Sex is bimodal, not binary” is a pithy, scientifically accurate and compassionate motto that is a welcome reprieve from the nuttiness of both the left and right on this issue, and one that I will try to remember. I think many would benefit from a basic philosophy class or two, where they would learn that the existence of some counterexamples do not necessarily render a system of classification meaningless – because unlike in mathematics, real-life definitions are inherently fuzzy. The color purple exists, but we can still generally distinguish between red things and blue things.

  18. I would certainly agree that biological sex in humans and most animal species IS strongly bimodal. I don’t fully agree with your criticism of the NY Times Opinion piece by Fausto-Sterling. Yes, she did not mention the numbers who don’t wholly fit the biological sex classifications, but I don’t see an attempt to obfuscate, as you state. Also, I’d like to point out that 1% of 300 million is 3 million people in the U.S. of A.
    And to the commenters above worrying about men claiming to be women to get into women’s bathrooms – ever seen one? Do you know any actual transgender people and what they had to go through before surgery? It takes years of counseling, hormonal treatments, trying out the gender switch BEFORE any surgery. They live in constant fear of being brutalized. Talk to someone who has undergone the switch – if they trust you they may tell you about it.

    1. “And to the commenters above worrying about men claiming to be women to get into women’s bathrooms – ever seen one?”

      If public bathrooms are like those in the U.S., most have partitioned cubicles that can be closed off. Unless someone is looking over or under the stall, the sex of the person using the stall should not matter.

      What about the new public unenclosed urinals in Paris?

      What about the many parts of the world which have no such facilities, and such functions are done au naturel?

      1. Bathrooms seem (to me) largely symbolic of other ways in which our society gives women separate spaces.

        Prisons is a major one: haven’t there been a number of high-profile cases of UK rapists declaring themselves female between arrest & being locked up?

        Sport discussed above. But there are also woman’s colleges, writing prizes, political offices, homeless shelters… it’s not clear that our society would be improved by these ceasing to exist.

    2. “Also, I’d like to point out that 1% of 300 million is 3 million people in the U.S. of A.”

      Jerry was not arguing that these people do not have valid issues, or that society need not become more accommodating and accepting of them because there just isn’t enough of them to matter. I won’t try speaking for him but I’d be surprised if the didn’t think, as do I, that it wouldn’t matter if there were only 1 such person, they are due the same respect and access to the benefits of our society as anyone else.

      I think that using the argument that biological sex is a social construct or that it isn’t very strongly bimodal to support the position that intersex, LGBTQ, transgender and other-gender people should be treated as equitably as any other group is unwise. For one, it’s a case of the naturalistic fallacy. Also, it is not accurate. This means you lose this argument which is bad for your case. And there is no need to make this argument. It is of no benefit and can actually be quite harmful to your case. Much simpler and much more direct to simply argue that these people should be treated as equitably as any others simply because this is the ethical standard that we want to uphold.

      1. This is the problem. People aren’t that stupid. When you tell them something like “There aren’t two sexes, everything exists on a continuum”, that person has only to look around themselves, see a bunch of men and women, and conclude you aren’t someone they should be listening to. So even if your heart is in a good place, trying to reduce bigotry, people are just less likely to listen to you if you try to soften them up with what is evidently false to them.

  19. In reality there is absolutely no reason to have sex on a birth certificate – at no time in the future should what sex appears on your birth certificate have any bearing on your choices in life. Gender is how we experience sex in our interpersonal relationships, making biological sex irrelevant on a day to day basis. If someone wants to compete at an elite level in sport or anything else and their status as male or female is being questioned, it isn’t because someone checked their birth certificate.

    The only reason for this move to create an issue out of something that isn’t one and motivate conservative voters. It’s really a statement about the way in which politics operates now.

  20. 1. The number one definition of sex in the Oxford Dictionaries pertains to sexual intercourse. Number two refers to male and female.

    Except for procreation, and sports, I see no reason for anyone other than the individual to have concerns about what sex they are. It especially should be no business of our government. Nor should parents and doctors make decisions for children about sex assignment, hormonal treatments and surgeries.

    2. In re reference to humans without ten fingers: Groups of humans define the characteristics of human beings in their group. Oddities often are not considered human and may be hidden or outcast if their
    anomaly can’t be excused or fixed.

    “Humans, like most of the other apes, lack external tails, have several blood type systems, have opposable thumbs, and are sexually dimorphic.”

    So, if a child of humans were born with a tail, it perhaps would not be considered human. Children are born with tails and many other anomalies.

    Look for human oddities, freaks and marvels in Wikipedia.

    Males in certain Native American Indian tribes who were physically male, but preferred female activities, were called berdaches, clothed in females clothing and
    performed female tasks.

    3. Regardless of ones chromosomes, cultural
    standards of male/female have a major impact on an individual’s perception of his/her

    Because my mother seemed more masculine than other mothers in my culture that I saw growing up, and my father seemed more feminine, I was confused about which I was until my teen years when I had a dream that answered that question for me.

    1. “child of humans were born with a tail, it perhaps would not be considered human”

      In 1350, perhaps. You can’t seriously hold that our society regards people with the wrong number of fingers, or chromosomes, as not being human.

      (They may get teased at primary school, but ginger hair is also sufficient for that.)

      1. That may be a bit of an exaggeration, but not by much. Individuals who do not conform to the standard physiognomy approved as normal by their culture, are often ridiculed and treated as freaks.

        Some are born with birth defects. Some are caused by by medications, surgeries, accidents, illnesses, insects (Zika), etc.

        I knew a boy in high school with webs between his fingers. And a girl who bounced when she walked because her Achilles Tendons wouldn’t
        stretch enough. And, a number of kids with scoliosis. And a family on my street when I was in high school that were all short, hairy and mentally retarded. My mother was the only person to give the daughter a ride home from the school bus when it rained.

        The following are from the first three entries in Wikipedia that come up if you search for “human oddities”:

        1. “Some call them circus freaks, human oddities and monsters – but they are truly human marvels.”

        2. “Explore Susan Tierney’s board “Human Oddities” on Pinterest. | See more ideas about Human oddities, Awesome and Babies.”

        3. “Ripley’s has always been a home to those deemed undesirable, freakish, or too shocking and strange to be part of “normal” society.

        Unlike those who mistreated and ostracized these individuals, here at Ripley’s we have always embraced the unique, the peculiar and the shockingly different.

        Feast your eyes on this group of utterly fascinating men and women with unique and startling physical attributes so unbelievable that you will question if they actually existed.”

  21. From the facts I can gather about this, the issue strikes me as a straightforward legal question. Title IX ban discrimination on the basis of sex by educational institutions that get federal money (with some exceptions.)

    Here’s the question: Does the word “sex” mean “sex”? Or does it mean “sex or gender identity”? The Obama administration decided that “sex” means “sex or gender identity”. The Trump administration is saying that “sex” means “sex.” This seems clearly correct to me, regardless of my own personal view on transgender issues concerning sex/gender segregated places. You can also view this as part of the centuries old “process vs. results” debate.

  22. “But we simply cannot maintain that sex is a social construct like gender.” But it is. That doesn’t mean that it isn’t at least in part (perhaps primarily) an attempt to provide us with the best understanding of how things are, but it’s still a concept that we as humans have created (and changed and disagreed about over time). I don’t think biological sex and gender are the same thing, but they are both concepts or ideas that we have invented. The idea that humans exist in a biological sex binary is silly. While there’s no way to be sure, if we stopped socializing kids into such binaries, I’m sure we’d see a much larger incidence of more people seeing themselves as something other than biologically male or biologically female. Let me be clear: I’m not saying that there are not any biological truths or facts involved; I’m just saying that human ideas, understanding, thinking, and constructs (and fights over these and changes in these over time) have shaped what is “real,” too. This is really not that controversial of an idea, nor is it that radical; it just flies in the face of what many (mostly older) people believe. Biological sex is not some inherent thing, and it’s certainly not a binary.

    1. I’m not quite sure what your point is. You both agree and disagree with the thesis.

      “I don’t think biological sex and gender are the same thing, but they are both concepts or ideas that we have invented”

      That seems a stretch. Sex is something we observe, not invent.

  23. Jerry, I don’t think your criticism of Fausto-Sterling’s article is accurate. In particular, you accuse her of ‘implying that because sex is not “binary” (i.e., there are some exceptions), that it is not bimodal. But I don’t see anywhere in the article that says or implies anything at all about how common exceptions to binary gender are, just that exceptions exist.

    In particular, her article is a response to people (and government policies) that exceptions to binary gender do not (or should not) exist. She says: ‘Today, some governments seem to be following the Roman model, if not killing people who do not fit into one of two sex-labeled bins, then at least trying to deny their existence.’ To refute this, all she needs to do is show that exceptions exist, not that they are particularly common; and that’s exactly what she does.

    1. And I think this is like the accuracy of statistics on the rape of females that don’t reflect all the unreported cases.

      More individuals might feel that they are females in a male’s body, or males in a female’s body than is reflected in the statistics. Effeminate males and masculine females suffer a lot of negative attention and bullying as they grow up even if they decide not to “come out”. As was pointed out earlier, the processes and surgeries that are required to make the outside reflect the inside is not rushed into or undertaken lightly.

      “Although the words gender and sex are often used interchangeably, they have slightly different connotations; sex tends to refer to biological differences, while gender more often refers to cultural and social differences and sometimes encompasses a broader range of identities than the binary of male and female.”

      Difficult to frame the law properly when the terminology is not discrete. Also, difficult to communicate meaningfully when we hold different definitions of sex and gender.

      1. This is about gender, though, not sex. The things are not one and the same, and Fausto-Sterling does her argument no favors by conflating them.

  24. The 1-2% numbers for “intersex” are likely WAY too high, and depend on an idiosyncratic definition of “intersex” that classifies every deviation from an alleged “Platonic ideal” of sex as “intersex”.

    For example Fausto-Sterling includes Klinefelter syndrome, Turner syndrome, and late-onset adrenal hyperplasia as “intersex”, even though Klinefelter-affect people are phenotypically males with a WORKING Y chromosome, and just have extra X chromosomes, Turner syndrome-affected people are phenotypically female with a missing X chromosome, and late-onset adrenal hyperplasia is a general term for many dysfunction in the production of sex steroids, which produces phenotype/genotype disalignement only in a small number of cases.

    If we accept the more reasonable definition of “intersex” as the births of children, when “intersex” means that chromosomal sex is inconsistent with phenotypic sex (XX males or XY females), or phenotypic sex is not classifiable as male or female, the number is MUCH lower, around 0.018% of births.


    Fausto-Sterling conflates biological sex, which is not only bimodal but INCREDIBLY close to binary if one assumes reasonable definitions of the binary, with self-identification with “gender”, which is a completely different issue.

    Gender disphoria, the perception of “not belonging” to one’s biological sex, is not related to intersex births.

    Estimates of how common disphoria is are unreliable and imprecise, and most people who experience gender disphoria are NOT intersex, neither according to Fausto-Sterling’s definition of “intersex” as a deviation from a “Platonic norm” of PERFECT congruence of the protypical phenotype and the prototypical phenotype, nor according to the more precise definition of clear pheno-genotype inconsistency or dubious phenotype.

    It would be better to separate physical sex from psychological gender rather than to try to spread misconceptions about physical sex to defend the rights of people whose psychological self doesn’t much their physical body.

    1. Dear Kirbmarc: Thank you for the correction and clarification. Also, for the reference to a source document. From a little additional reading, I now see that not only is “intersexual” distinguished “transexual” and “transgender”. But, on an LGBT web site, these latter two categories were defined differently from each other.

      I’m sorry for not being more knowledgable in this area. I wish I were. It doesn’t keep me from having an opinion however. My main concern is individual freedoms, particularly in the areas of sex and gender. No one but the individual(and his/her doctors) should have anything to say about the sex and gender choices of any other person. I am especially angry at the religious right and our government who delve into what should be personal matters and want to very strictly define sex and gender (whichever one they really mean) for legal purposes.

  25. I don’t for the life of me understand why people are so obsessive about other people’s sex (in probably every sense of the word). Why can’t people can’t simply accept other people’s genders as they accept other people’s shoe sizes?

    Is there biology behind this or is it simply a cultural deformity?

    1. Because unlike shoe sizes, biological sex being binary is a scientific fact that person are trying to dismantle which will lead to widespread confusion in younger people especially how puberty and the act of sexyal intercourse works and is explained if even the human body’s reproductive organs are seen as a “social construct.”

      Then add trans “women” invading female spaces and competing and winning female sports as well as taking educational opportunities from women.

      Then add how some extremists even want to delete gendered language all together forcing the majority to re-learn languages which is especially difficult for strongly gendered languages like the Romance languages.

      Biological sex on the whole is a scientific reality and affects much of our life whether we like it or not and forcing society to completely change it’s scientific idea of biological sex based on the abnormalities of the 0.018% is extremely unfair and dangerous.

      1. I wouldn’t use the word “abnormalities” for people who don’t slot into the gamete bimodality, as that word would insult those people. “Exceptions” is probably better.

  26. I wish you would try to get an op-ed published in a major newspaper or media outlet. Maybe you have? We desperately need a corrective to the Fausto-Sterling perspective, which is being pushed heavily and accepted widely by the media. Gender has become a battle ground and faulty post-modern notions of gender are going largely unchecked by scientists. The belief that gender is innate and sex is a social construct is being widely promoted and it is an exact inversion of reality. Thank you for writing this, and I hope you will continue to speak publicly about it

  27. I’d like to ask a question. It’s my understanding that no matter what the intersex condition, no human has ever produced both male gametes and female gametes. They either produce one, the other, or neither. Is this correct?

    And if it is, isn’t this a meaningful constraint on what “intersex” can mean? That is, no matter what your anatomy or alleles, if you produce male gametes, you are male. If you produce female gametes, you are female. Only if you produce neither would you have to resort to investigation of anatomy and chromosomes.

  28. “What this means is that if you do a plot of sex versus frequency in which you combine all traits that define “males” (above) at one end and those defining females at the other, and then plot the frequency on the Y-axis, you’ll get a plot with two distinct and widely-separated peaks, with a valley containing some intermediates (intersexes and the like) between them. This is what I mean by the bimodality of sex”

    If this cannot be described as binary or effectively binary, is there biological phenomena that could ever use this word? Would there not always be complex exceptions, even if just a single aberration? Perhaps binary is being reserved only for the domains of mathematics and purely theoretical analytic logic.

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