My letter about binary sex in the San Francisco Chronicle

June 6, 2023 • 10:30 am

Here’s more about biological sex, which has become a hot and contentious topic in politics.

Two days ago I described and criticized an op-ed piece in the San Francisco Chronicle by Ash Zemenick, a biologist who works for the University of California at Davis. (He was also first author on a BioScience paper that I criticized.)  The link is paywalled, but if you want to read Zemenick’s piece, it’s archived here.  Here’s the title:

Zemenick’s point, which he tried to make but failed, is that sex in humans (like gender) is non-binary because traits like sex chromosomes, hormones, and genital morphology are non-binary. He dismissed the correct definition of sex, based on gamete size, this way:

Now, let’s consider the most reductive definition of sex. The gametes. What are gametes? Reproductive cells. Eggs and sperm. Sounds binary, right? As a human, you either produce eggs or sperm, yeah? Nah. On average, most cis women and trans guys are born with all of the eggs they may eventually ovulate with. But some are born without them. Some have their ovaries removed. So, they have no gametes. What about them? Cis men and trans women don’t even start producing sperm until the onset of puberty. So, before puberty, they have no gametes. None. Some cis men are sterile. What about them? As you can see, some people, for these reasons, don’t produce or have gametes at all. Therefore, there are three states: no gametes, eggs or sperm. It’s a triplet, a trifecta. Gametic sex is not binary.

As I said, that’s bogus because the biological definition of sex involves having the reproductive equipment to make either small mobile gametes or large immobile ones. This doesn’t require that your equipment is actually functional.  Zemenick’s op-ed simply knocked down a bunch of straw men. Why? Well, Zemenick identifies as non-binary, and I suppose he was trying to find justification in nature for his own gender.  But you don’t look to nature simply to justify your identity. Nature is as it is, and humans are the only animal with members claiming “genders.”  All other animals have biological sexes.

At any rate, I couldn’t let this op-ed go by without trying to correct its biological errors, for it appeared in a big important newspaper. So I wrote a letter to the editor of the Chronicle that was published today. It’s paywalled at the link given in the headline below, but I’ve put a copy below the title.  It speaks for itself. (It’s short because I was limited to only 200 words.)

UPDATE: I’ve now found the letter archived here.

69 thoughts on “My letter about binary sex in the San Francisco Chronicle

  1. Do they allow Letters to The Letters To The Editor? If so, I look forward to hearing what readers have to say about your letter, (which is, as usual, beautifully succinct).

  2. To people like Zemenick, this excellent rebuttal is like pearls before swine, but many others who read it will be reminded of a simple but important biological concept – one we all understand at some level- put so concisely well.

  3. Very concise and well written.

    Facts don’t go away simply because they don’t comport to one’s world view. That’s one of the beauties of science. It seeks truth irrespective of ideology.

  4. Lately we have been treated to an extraordinary focus on those who demand from the rest of us incessant affirmation of their chosen “lived biologies and experiences”. It is revealing that the word “affirmation” crops up so often here. Distinct from those who just go about living their “lived biologies and experience”, the noisy sub-group fit the Mayo Clinic’s definition of a personality type: “Narcissistic personality disorder is a mental health condition in which people have an unreasonably high sense of their own importance. They need and seek too much attention and want people to admire them.”

    A sociological question: by what tactic did this narcisso-diverse subgroup garner so much attention in the last decade or so? A partial explanation is surely their use of postures and clichés previously associated with the political Left.

    1. While I’m firmly in JC’s camp, I think “they” would argue that, because they’re the target of physical and political violence, that’s what justifies their ‘incessant affirmation”. Given what state legislatures are attempting in several red states it’s hard to argue that fact. Still, they only hurt their cause when they publish articles like Zemenick did.

      1. So do you think the author was a target of physical and political violence. Ash never mentions it. And legislation is not “violence”; it’s legislation, which should be opposed, but I don’t see how that justifies people demanding incessant affirmation.

    2. The overall objective of queer theory is to use the self to transform society – by living queerly – in particular the systems of power that assert distinctions such as either male or female. These distinctions are inscribed on bodies (Judith Butler). Thus, over many generations, the society will eventually have no such distinction to inscribe upon bodies, leading to potentialities of experience unreachable because of our current state of bodily imprisonment. So “affirmation” is a sign of that transformation of society, because nobody wants to be unkind.

      I didn’t make that up – it is a blend of Rousseau, Halperin, Foucault, Judith Butler, shades of Marx and Hegel, and more as explained by James Lindsay.

      There is an impetus to avoid being punished by society for being a -phobe of any sort, or being unkind, or confrontational. The idea of “affirmation” sounds consistent with “life, liberty, and pursuit of happiness”, and completely new and independent of any ideological force. But the post modern writing and more is there for all to read. Somehow, it never comes up – the way one’s religion or diet choices is not questioned – a patronizing politeness or respect? Why wouldn’t anyone want to discuss transformation of society?

      Sorry for the length. I’m trying to keep my latest epiphany – from a James Lindsay podcast – in control.

    3. So very true. And those who pander to the narcissists usually always have something to gain because then it’s not so hard to actually *believe* that 2 plus 2 makes 5. Now is the perfect time to re-read 1984 and Bob Triver’s wonderful work on self deception.

  5. Excellent letter Jerry, easy to read and easy to understand.

    The thing that gets me, and this is a positively normal failing among humans in general, is that there is absolutely no good reason and no advantage to maintaining the claim that sex is not binary in order to promote equal rights and respect for Transgender people. It is entirely beside the point, non sequitur, doesn’t matter.

    In reality it is a big disadvantage, and it just becomes more so the longer and more ferociously you insist on it. It gives your opponents easy ammunition against you, it’s an own goal. It puts you at odds with your natural allies who differ only in not denying reality, and it inspires you to think of them as your enemy too.

    Apparently the human animal has evolved to deny reality despite any amount of evidence to the contrary when it comes to issues that evoke a strong ethical commitment.

    1. Yeah and it’s somewhat ironic because the bigotry against gays was that “it’s unnatural” and therefore invalid and gays are somehow delusional or perverts. Now we hear the nature argument again and it is still just a bad argument. We don’t need nature to justify everything. Nature can be deleterious to our flourishing.

      1. The naturalistic fallacy has a profound grip on human minds (mine included). It may be a fallacy. However, it is also very pervasive.

    2. Exactly this: “…there is absolutely no good reason and no advantage to maintaining the claim that sex is not binary in order to promote equal rights and respect for Transgender people.”

      And this: “It puts you at odds with your natural allies who differ only in not denying reality, and it inspires you to think of them as your enemy too.”

      The more the trans-activism community insists on denying biology the less charitable I find myself to their cause. I know I’m not alone. The comments on most NYT articles that are trans-related or trans-adjacent are filled with well-meaning liberals like me that are increasingly feeling like we’re perceived as the enemy simply because we can’t get on board with denying biology. When supporting rights isn’t enough, when you have to deny biology to be an “ally,” that’s veering right into Orwellian territory.

    3. “… there is absolutely no good reason and no advantage to maintaining the claim that sex is not binary in order to promote equal rights and respect for Transgender people.”

      What then might be another explanation?

      I would posit to keep post-modernism going, especially the domain of queer theory. It is the design of that Byzantine yet simplistic formula – to problematize, antagonize norms (conflate the descriptive “normal” with moral “normal”), raise critical consciousness, etc.

      I find my claim hard to believe, but from reading Lindsay’s analysis, it seems to fit the observations – especially the irrelevance of observation or empiricism, and as interestingly noted below, induction.

      It is why I feel PCC(E)’s letter can be deemed just a “privileged” “opinion” by virtue of PCC(E)’s “positionality”

    4. You are correct (in my opinion) in asserting that Transgender rights and the sexual binary are not particularly related. However, I do see a method at work here. A key goal of the identity politics left is to undermine all of the certitudes that people have traditionally based life on. In a bygone era, Orwell used 2+2=4 as an example of a proposition that no one could disagree with (unless the Party claimed otherwise). Of course, I am not faulting Orwell for asserting 2+2=4. However, these days 2+2=4 is vigorously disputed.

      I think the above is part of it, but not of it. In the minds of TRAs, viewing sex as a spectrum, somehow make trans more legitimate.

  6. Whether sex is binary or not is indeed irrelevant to whether trans people deserve the same equal rights and respect as any other group, but it’s very relevant to whether or not gender replaces sex in the definition of men and women.

    The right they want is to be believed, rather than simply humored or accommodated. That can’t happen if it still makes sense to continue using sex as a reliable method of classification.

  7. Thank you for correcting the record for the readers of a “big, important, newspaper”, keeping them from being swept down another woke, rabbit hole. It is really important for subject matter experts to correct woke rubbish of high visibility on matters such as this and on statements that confuse or conflate equity with equality. Please keep at it!

      1. If that were really true why would it seem like you are so often not just on point, but on fire? 😉

  8. Comment #12 points out: “…there is absolutely no good reason and no advantage to maintaining the claim that sex is not binary in order to promote equal rights and respect for Transgender people. It is entirely beside the point,”. Why, then, do we see this claim so often? Maybe it is an example of echopraxia: someone, somewhere suggested it, and then a clowder of copycats could not stop themselves from repeating it, over and over. It
    might be amusing to trace down the original source, presumably somewhere in the arcana of Critical Gender Theory. As to why some bullshit assertions are copied endlessly while some are not—that</b is a serious puzzle in social psychology. Wait a minute, I feel the title of a new academic discipline coming on: Critical Bullshit Theory.

    1. I can, and do, devise rationalizations that might explain it, but damned if I know. I think in general terms it illustrates that old cliché that in humans emotions often trump rationality, and the stronger the emotions the more likely rationality is bypassed. And emotions like righteousness and indignation are powerful and addictive. At least, that’s one story.

    2. Lorraine Daston: Against nature. MIT Press, 2019, 96 pages
      Publisher’s description:
      Why have human beings, in many different cultures and epochs, looked to nature as a source of norms for human behavior? From ancient India and ancient Greece, medieval France and Enlightenment America, up to the latest controversies over gay marriage and cloning, natural orders have been enlisted to illustrate and buttress moral orders. Revolutionaries and reactionaries alike have appealed to nature to shore up their causes. No amount of philosophical argument or political critique deters the persistent and pervasive temptation to conflate the “is” of natural orders with the “ought” of moral orders.

      In this short, pithy work of philosophical anthropology, Lorraine Daston asks why we continually seek moral orders in natural orders, despite so much good counsel to the contrary. She outlines three specific forms of natural order in the Western philosophical tradition—specific natures, local natures, and universal natural laws—and describes how each of these three natural orders has been used to define and oppose a distinctive form of the unnatural. She argues that each of these forms of the unnatural triggers equally distinctive emotions: horror, terror, and wonder.

      Daston proposes that human reason practiced in human bodies should command the attention of philosophers, who have traditionally yearned for a transcendent reason, valid for all species, all epochs, even all planets.

      From the book’s Amazon site:
      Lorraine Daston is Director at the Max Planck Institute for the History of Science in Berlin and Visiting Professor in the Committee on Social Thought at the University of Chicago. She is the coauthor (with Katharine Park) of Wonders and the Order of Nature, 1150–1750 and (with Peter Galison) Objectivity and the editor of Things that Talk: Object Lessons from Art and Science, all three published by Zone Books.

      1. True you can’t get from an “is” to an “ought”, —you run into the Naturalistic Fallacy if you try—but that doesn’t stop people from trying anyway. If “We the People” believe our creator has endowed us with certain inalienable rights and we are going to fight against the King who, acting tyrannically, tries to deny them to us, isn’t that precisely trying to get from an is to an ought? In this case rights are being conjured up out of nature even though they are never actually observed “in nature.” Indeed, most of what you actually observe in nature gives no purchase to rights of any kind.

        1. It seems to me you have matters somewhat backwards. Kings claim a “Divine Right” to rule with no evidence that the rains refuse to wet their heads. The call for “inalienable rights” is just a way of saying “put up or shut up.” Kings don’t have to be tyrants to oppress. Kingship itself is unjust. And why take the “creator” talk seriously? The “creator” isn’t the God of the Bible, the source of the “Divine Rights” of kings.

          1. Backwards about taken well point make you.

            But by 1774, English kings no longer ruled by Divine Right. Parliament—elected by male commoners who owned property as the nascent U.S. would soon do—constrained the King’s executive power considerably and more-so every year, by refusing his requests to raise taxes (in England if not the colonies.) The Quebec Act of 1774, one of the “Intolerable Acts” that led directly to the Revolution, was an Act of the British Parliament, not a Royal Decree. The 13 Colonies wanted self-rule to be out from under the thumb of a foreign government, not just a king. The Revolution would have happened even if England had been itself a democratic republic with you-all as non-voting colonies.

            What I’m really meaning here is that there is no “creator” who endows rights “naturally” and “self-evidently” to commoners or to kings. Rather, rights are contingent, negotiable, and situationally fluid. You have to fight for them against people who want to take them away from you. As a free-speech absolutist of the American variety (even though I’m a foreigner), I don’t have an easy answer to the person who disagrees with my strong 1A argument and who says instead, “I think your dangerous ideas should be silenced, otherwise we’ll never stop Covid, or climate-change, or Islamophobia, or whatever.”

            This might be anticipating a tweet Jerry referred to about demonstrators who silenced a speech by Sen. Joe Manchin. I hope he expands it into a Hili so I’ll let him speak first.

            1. You say “rights are contingent, negotiable, and situationally fluid.” If your rights are contingent upon the whims of another, do you really have rights? Which of your rights are you willing to negotiate away? If situations change what rights are you willing to surrender?

              About rights you say “You have to fight for them against people who want to take them away from you.” But if you really think “rights are contingent, negotiable, and situationally fluid,” it sounds like you have no interest if fighting for rights in the first place. Please explain.

              1. This is an active field of discussion in political philosophy that I can’t do justice to. I just have friends in that discipline whom I try to follow along with. There is a problem with absolute rights. Paul Viminitz puts it this way, paraphrasing:
                Suppose you believe that every woman has an absolute right to control her own fertility, a view that would not be controversial here, and it gets enshrined as a Constitutional Amendment.. (Ignore religious objections as we do.). Now suppose a pandemic kills most of the children and leaves all but six women in America permanently infertile. How long do you think those six women would be allowed their right to not have children? One way or another, they would all be pregnant for the rest of their reproductive lives, as would their daughters, and to hell with the Constitution. Abortion and contraception would have to be rigidly prohibited, even with preventive incarceration. A woman who thought she still had the right to control her fertility would have to fight off (literally, with violence) those men and women who were trying to make her do her bit to repopulate the country. She might negotiate a deal where she would get free obstetrical care as her price not to shoot any man who came near her.

                So the right to control fertility is contingent on the polity being able to afford voluntary infertility. Disputes may involve violence but only if the person values the claimed right enough to fight. And there is some room for negotiation because the polity understands that holdouts can’t just be killed, for then they couldn’t get pregnant. And as the country gradually repopulated, law-makers could come to accept more fertility autonomy as the emergency receded.

  9. Hume denied induction.
    We are now paying for it.

    The concepts with the English-language labels “woman” and “man” were induced by isolating the essential characteristics of existents in existence, namely human specimens, and then dropping the “measurement.” (size, age, appearance, etc.)

    This inductive method of conceptualization (combined with deductive method of investigation), is fundamental and necessary for reason/science. It is certainly how the taxonomy of the Tree of Life is established and maintained. It is how science works and the only way science works. Reason.

    Hume threw a stupid blanket of vapid doubt around it. Kant was not opposed. Nor Hegel … all the way down to Popper.

    So now, a fool like this guy can point to a specific instance of an adult human woman who has had her essential characteristic of ovary/gametes surgically removed as “not a woman.” That’s a rude insult to induction.

    It is a trapdoor down into hell.

  10. “Biologists define sex not by the many traits Zemenick lists, but in this simple way: Males are the sex with a reproductive system designed to produce small, mobile gametes (sperm), while females have reproductive systems designed to produce large, immobile gametes (eggs). Note that you don’t actually have to produce gametes, for some people are sterile or post-reproductive. But there is no sex other than these two.” – J. Coyne

    It is very interesting that here you state explicitly that actually producing eggs/sperm (during some life phase) is not a necessary condition for being female/male. So what is both necessary and sufficient for an animal’s being female/male is having ovaries/testicles. To put it more precisely, since there are females/males who no longer have ovaries/testicles: Having some temporal part (* with ovaries/testicles is both necessary and sufficient for an animal’s being female/male. That temporal part may be a past one.

    (* If organisms are regarded as four-dimensional objects, they have both spatial parts and temporal parts:

    1. Footnote: If hermaphrodites are taken into account, my definitions must be formulated as follows:
      1. An animal organism is (only) female iff it has some temporal part with ovaries and no temporal part with testicles.
      2. An animal organism is (only) male iff it has some temporal part with testicles and no temporal part with ovaries.
      3. An animal organism is simultaneously hermaphroditic iff it has some temporal part both with ovaries and with testicles.
      4. An animal organism is sequentially hermaphroditic iff it has some temporal part with ovaries and some other temporal part with testicles.

    2. If what you are saying is true and it sounds reasonable, so what? All you are doing is refining the argument in quasi philosophical terms while maintaining the position that those that have the equipment, at some point, to generate a particular type of gamete, is the sex that generates that type of gamete.
      As there are only two types of gamete there are only two sexes.

      The equipment is not transferable between individuals therefore a person cannot change their sex.

      Other than that, what are you trying to say?

  11. “So what is both necessary and sufficient for an animal’s being female/male is having ovaries/testicles.”

    No. Development can be tricky and problems may occur such that testicles or ovaries do not develop. There are also, of course, eunuchs and women who’ve had hysterectomies. None of these people have the organs to produce the gametes they are biologically programmed to but all of them are of one or the other biological sex. They are either male or female and it would be both dishonest and insulting to call them something else.

    1. Please read what I write after the above-quoted sentence!
      If having some temporal part with ovaries/testicles is both necessary and sufficient for being female/male, then individuals having no such temporal part due to gonadal agenesis are sexless (neither male nor female).

      “…They are either male or female and it would be both dishonest and insulting to call them something else.”

      If you think that neither gametogenesis (oogenesis/spermatogenesis) nor gonadogenesis (oophorogenesis/orchiogenesis) is necessary for being female/male, then what’s your alternative definition?

        1. Is cathood biologically defined in terms of having a tail? No, it isn’t! Is manhood (maleness) or womanhood (femaleness) biologically defined in terms of producing gametes or possessing gonads (designed to produce gametes)? Yes, it is!

          1. Good lord. You are so close.

            To parapharse you; Is maleness biologically defined in terms of having a testicle? No, it isn’t!

            Please read Dr PCC(e)’s excellent letter to the editor in today’s SF Chronicle for the answer about how we actually define biological sex. A copy can be found above.

            Last from me….

            1. “Males are the sex with a reproductive system designed to produce small, mobile gametes (sperm)…” – J. Coyne

              The testicles are that part of the male reproductive system which is “designed to produce small, mobile gametes (sperm).” So maleness is (implicitly) defined by Prof. Coyne in terms of having (some temporal part with) testicles. That is, maleness doesn’t require actual spermatogenesis (development of sperm), but it requires actual orchiogenesis (development of testicles) at least. And if orchiogenesis has occurred in an organism, it thereby has some temporal part with testicles. (The present temporal part of a castrato has no testicles, but a past temporal part of him has; so he is still male.)

          2. No it isn’t! Maleness is defined as having a body plan of organs intended (in teleological shorthand) to produce and conduct sperm. And femaleness is defined contra-analogously.

            If an embryo develops without gonads, the baby’s sex will still be ascertainable by the conducting structures that develop. (The person will never become fertile, of course.). In most cases for embryological reasons, the conducting structures will develop along female lines because this is in some senses the default when there is no gonad to drive the process to complete sexual development..

            1. Given Prof. Coyne’s definition, I fail to see how a sex can be ascribed to organisms affected both with gametoagenesis (non-development of gametes) and with gonadoagenesis (non-development of [post-bipotent] gonads). Note that genetic or phenotypic characteristics (other than gonadal ones) are totally irrelevant to his definition of the two sexes!

              1. I don’t believe they are. For one thing we never observe the gonads directly except during surgical operations. We impute the presence and sex of gonads from observation of those phenotypic characteristics which you claim are totally irrelevant. We can’t be proved correct in our imputation until the person fathers or mothers a child…or until a person with female genitalia begins to have regular menses, implying that she is cyclically ovulating. If a person never tries to have children, or never gets regular menses, you really can’t say what sex s/he is, according to your definition, which is absurd.

                By the time most people will be discovered to have defective or absent gonads they will have been living as girls usually (but occasionally as boys in the case of 46, XX individuals who have the Sry gene translocated to the paternal X chromosome) for at least 14-16 years. Even if found to be “sexless” in a reproductive sense, you are not going to change their birth certificates from the phenotypic determination their parents made at birth.

              2. You’re confusing two different questions: (1) What does it take for an individual to be female/male? (2) How can we find out whether a given individual is female/male? An answer to question 1 provides a /definition/ of femaleness/maleness, whereas an answer to question 2 provides /empirical criteria/ for, or /observable symptoms/ of femaleness/maleness. Certain phenotypic or genetic features are (reliable yet fallible) species-relative indications of an organism’s sex; but these are not part of the biological definition of sex, to which normative questions concerning a person’s legal sex status are equally irrelevant.

              3. Then I want to ask you: A typically normal baby boy is born and grows up through normal adolescence and puberty. He has erections and ejaculatory orgasms. He gets married at 25. He and his wife desire children but no conception results. His doctor finds normal anatomy but no spermatozoa in his ejaculate. Investigation shows him to be 46, XX, Sry +ve. You could do a biopsy of a testicle but no need. Without an intact Y chromosome with genes in cis no spermatogenesis is possible.

                So: what sex is this person?

                To save more to and fro, I’ll sign off with the observation that if you make any answer other than “male”, then you and I aren’t speaking the same language. Which is fine.

                And, as others have said, none of this has anything to do with trans people, except that they want to get us to admit that sex isn’t binary in order that we can be compelled to say that men can be women. Gender doesn’t quite do it for them.

  12. Great letter Dr. Coyne. I’m very happy it was chosen for publication because in a few short words you exposed the falsehoods proposed by the other author you reference

  13. Jerry, when you write that about 1 in 5500 humans is an exception to the sex binary, do you mean the 0.018% “intersex” individuals from Fausto-Sterling and the rebuttal by Sax?

    I don’t think you need to make even this tiny concession to the sex-is-a-spectrum folx. People with DSDs are still male or female, it’s just sometimes hard to tell from the secondary sex characteristics (cf. Caster Semenya).

  14. I had to laugh at the graphic showing a very strange pairing of nucleotides, G with T, C with C etc. is that where the problem arises ? Ignorance of basic genetics in the general population ?

  15. My favorite visiting cat a few years ago had polydactyly of the forepaws—presumably a demonstration that the number of digits is not unimodal, but is “on a spectrum”. As I have noted before, the existence of XO, XXY, and trisomy 21 individuals no doubt tells SF Chronicle illuminati that the human chromosome number is also “on a spectrum”.

    Once again, the only interesting question raised by this matter is the sociological puzzle of how nonsense statements achieve so much currency. Thinking about common beliefs in fascist and communist states, we used to ascribe it to state propaganda. Of course other routes exist, of which religious faith is the most obvious historic example.

  16. “…This standard definition applies not just to animals but also to nearly all plants, and is indeed binary.” – J. Coyne

    “Anisogamy is universal in most sexually reproducing multicellular plants and all multicellular animals. Plants (defined here as Viridiplantae: green algae and land plants) present some exceptions to this: for example, the multicellular colonial green algae genera Pandorina, Volvulina and Yamagishiella are isogamous as are some multicellular marine green algae[.]”

    (Lehtonen, Jussi, Hanna Kokko, and Geoff A. Parker. “What do isogamous organisms teach us about sex and the two sexes?” /Philosophical Transactions of the Royal Society B/ 371/1706 (2016):

    Are isogamous green algae the only exception to the standard definition among the plants? Are there isogamous land plants?

    (I read that brown algae, golden-brown algae, golden algae, and yellow-green algae are now taxonomized in the kingdom of chromista rather than in the kingdom of plants.)

    By the way, the authors write that “maleness is synonymous with the production of small gametes.” If that’s the standard definition, then organisms which never produce small gametes are not male. But according to your definition and your statement that “you don’t actually have to produce gametes,” maleness is /not/ “synonymous with the production of small gametes.”

    1. I had inadvertently failed to notice that the above-mentioned paper (Lehtonen et al.) gives an answer to my question as to whether there are isogamous land plants. The answer is no.

Leave a Reply