Why Sex Is Binary

Having had, last night, a lively conversation over dinner with a woman who chid me (and sought to correct me) for insisting that sex is indeed binary, I think a clarifying post is in order.

Before I begin, I’ll pause to express surprise and dismay at how stubbornly fashionable, and how prevalent, denial of the fundamental dualism of sex has become, and remains; it’s a distressing symptom of the radical deconstruction and obliteration of all objective principles and categories that has grown, from small clouds of doubt at the beginning of the Enlightenment, to the ruinous tempest now smashing everything in the West to rubble. To insist, in these times, on the objective reality of the sex binary is to make oneself (as, for instance, J.K. Rowling has done) a heretic and a pariah. Nevertheless, there it is.

What is sex? Why does it exist? Why does it seem to be, in all species, a driving force whose urgency is second only to — if not primary to — the will to survive? Why does every human tradition always and everywhere, without exception, distinguish between male and female, not only as essential biological types or social categories, but as fundamental — and binary — divisions of transcendent metaphysical order?

The universal (until five minutes ago) human consciousness of the centrality of sexual duality, and its inclusion in the traditional systems of every culture, surely indicates something vitally important. I want to make this case as simply as possible, though, with the broadest possible appeal in this secular era, so I’m going to leave tradition and metaphysics out altogether — but not before I point out that duality and polarity are the very essence of sex; it is only the existence of the twin concepts of male and female that give the idea of sex any meaning at all. That said, though, we can imagine all sorts of binary concepts — hard and soft, black and white, awake and asleep, tall and short, loud and quiet, beautiful and ugly, friend and enemy, etc. — that are extremes of continua, and allow for the existence of intermediates. Biological sex, however, is not like that.

Why does biological sex exist at all? The answer: it exists, simply and unambiguously, as a mechanism of reproduction. It is how most multicellular organisms, and some unicellular organisms, reproduce. The mechanism involves the fusion of two sex cells, or gametes, each carrying half of the complete genome of the newly created organism (which before subsequent division is now a single, fertilized cell called a zygote).

In all multicellular organisms, with the exception of some yeasts and fungi, gametes come in two (exactly two) strikingly different forms. This is called anisogamy, and it is probably at least a billion years old. The male form is sperm; it is small (too small to see with the naked eye, and first observed by pioneering microscopist Anton van Leeuwenhoek in 1677), and it is motile. It has a tiny head, and a long whiplike tail that it uses to swim. The female form is the egg, or ovum; it is one of the largest human cells, and is large enough to see with the naked eye. It has a volume ten million times that of a sperm cell, and unlike the sperm, it is unable to move on its own.

These two kinds of sex cells — the two complementary components of human sexual reproduction — are all there is. There is no intermediate form, or mixture, or chimera, nothing halfway between a sperm and ovum. All human gametes are one or the other, and in biological terms, the combination of sperm and ovum to create new life is what sex is. There’s nothing cultural about any of it, and nothing that is a matter of opinion. As far as objective scientific facts go, this is as solid as it gets.

Those claiming that sex is nevertheless non-binary will now point to the indisputable existence of hermaphrodites, both human and animal. There are people with all sorts of ambiguous sexual characteristics, and there are animals that switch sexes during their lifespan, or even instantiate both sexes at once. Doesn’t that mean sex is a continuum?

No.

It’s important at this point to reiterate, and keep in mind, what sex is: a mechanism of reproduction involving the fusion of male and female gametes. The embryonic development, morphology, and life-cycle physiology of animal bodies can vary, and be disrupted, and make errors, in various ways, but the underlying mechanism of sex itself never changes at all.

Biologically, there are three forms of hermaphrodites — comprising two forms of “true” hermaphrodites, sequential and simultaneous, and what are called “pseudohermaphrodites”.

Sequential hermaphrodites are animals that produce female gametes at one stage of life, and male gametes at another. Protogyny is when they start out as female and become male; the opposite is protandry. Some species go back and forth! (All three of these sequentially hermaphroditic forms can be found among reef-fish such as clownfish and wrasses; sometimes the changes appear to be induced by social-dominance hierarchies. The details are fascinating.)

Simultaneous hermaphrodites are animals that can produce both male and female gametes at the same time. This is mostly found among snails and slugs, but there is one known vertebrate species — the mangrove killifish, Kryptolebias marmoratus — that pulls off this trick. Animals that can do this can do sexual reproduction all on their own.

Pseudohermaphrodites produce only male or female gametes, but exhibit secondary morphological characteristics of the other sex. The example usually given is the female spotted hyena, which has what appears to be a penis, but is in fact an enlarged clitoris that functions as a birth canal.

Regarding humans: nearly every instance of “intersex” morphology is pseudohermaphroditic. Sequential hermaphroditism does not exist in any terrestrial vertebrate (and so not in humans), while simultaneous hermaphroditism — known formerly as “ovotestis” — is vanishingly rare; only 500 cases or so have ever been reported, and the bulk of those merely involve the presence of both male and female gonadic tissue, with actual production of both sperm and ova being even rarer (I haven’t yet to be able to determine if any examples of that have ever been seen at all).

What should be clear after looking at all of this is that even the various forms of hermaphroditism — even having both ovaries and testes — provide no counterargument to the underlying duality of sex. They offer no examples of any sort of intermediate, hybrid components of the essential, binary mechanism of sex; they are merely various ways of producing one kind of gamete or the other (or both). This stubborn duality means that biological expression of the mechanism of sex only exists in four, clearly delimited forms:

1) The production of male gametes;
2) The production of female gametes;
3) The production of both;
4) The production of neither.

If sex were truly “non-binary”, there would be a vast continuum in between all of this, a vague and fuzzy biological domain in which sexually reproducing beings used something other than sperm (male) and ova (female) — some spectrum of gametes that are neither wholly one nor wholly the other — to create new life. But in the billion years of sexual life on Earth, such a thing has never existed, and it doesn’t exist now.

Sex is binary.

14 Comments

  1. Another Dave says

    And did you explain all of that, in the terms you used above, to the idiot you had dinner with?

    I realize you live on the Cape, and are surrounded by, and therefore forced to interact with, New Englanders who live enveloped in a thick haze of Liberal Confusion about the true nature of objective reality, but I am curious if you spelled any of this out to this lost soul.

    Posted May 18, 2024 at 11:15 pm | Permalink
  2. Malcolm says

    In fact, Dave, I did, and the reason I posted this was because I wanted to write down all the things I’d said.

    And I’ll say also that the person I had this conversation with wasn’t an idiot at all, but a highly intelligent woman who simply had begun the process of reason from wildly different axioms.

    Posted May 19, 2024 at 1:22 am | Permalink
  3. Locust Post says

    Nice summary. I find debating about beliefs that are counter to simple and easily observed reality to be exhausting as you are debating with crazy. Nice grooming and some literacy can put a respectable face on the belief, but it is still crazy.

    Posted May 19, 2024 at 6:35 am | Permalink
  4. John says

    Enjoyed your words, as usual, Malcolm. Sad to have to admit the necessity to argue it though, when it seems such a basic truth.

    Posted May 19, 2024 at 9:01 am | Permalink
  5. Anti-Gnostic says

    I recall hearing radio reports about the Jonestown massacre and realizing that people can make themselves believe anything.

    It’s become downright frightening to see what otherwise intelligent, sophisticated people will swallow: COVID, the ghoulish transgenderism, diversity–especially espoused by people living behind walls of high property values, and on and on. You may as well debate the Real Presence with Catholics.

    If you don’t already, you should read marginalrevolution.com to see what our elite and professional classes believe. It’s like stepping through a mirror. Our cognitive, financial and political elite occupy a different mental space. I think when you get to the point that you can just print the money that’s what happens.

    Ideology is the curse of mankind in my opinion. We will either evolve out of it, or it will end with the Great Filter.

    Posted May 19, 2024 at 9:21 am | Permalink
  6. Another Dave says

    Malcolm, with all due respect, any individual who takes a position contrary to established biological reality is an idiot, no matter how well educated or credentialed.

    Posted May 19, 2024 at 7:12 pm | Permalink
  7. Malcolm says

    Your argument is not unpersuasive, Dave.

    Posted May 19, 2024 at 7:32 pm | Permalink
  8. Jason says

    Perhaps the issue is more subtle than that of biological binarism, which as Another Dave says you’d have to be a complete moron not to recognize. Rather, it’s the thousands of instances in which a superficial blank slate manifestation sex differences shouldn’t matter, but they indeed do in a very profound and visceral sense as a result of evolution. I remember reading years ago about some Canadian legislator whose nurse-wife came home after a long night shift. This Marge figure from “Fargo” proceeded to shovel the driveway, with her hubby showing his gratitude by cooking her a fine breakfast. As can be imagined after the fool posted all this on Twitter, the brouhaha was epic, with the female audience bringing the hammer down hard on the poor fellow. The irony of it is that if the sex roles had been reversed, nobody would be batting an eyelash. “Oh what a wonderful, hardworking man you must have!” the feminine chorus would gush. “I wish myyyy husband was like that!”

    Posted May 19, 2024 at 7:41 pm | Permalink
  9. Malcolm says

    Well, Jason, I’ve cooked my wife many a meal, and she’s always been the family bookkeeper.

    Sexual roles and behaviors and manifestations have shades and nuances and motives and secrets beyond counting, and I’ll gladly agree with anyone who says so.

    But sex — biological sex — is as binary as electrical charge. And that’s what my interlocutor, along with so many others, was denying (as if I was an ignoramus who ought to know better, I should add).

    But getting back to your point, you might enjoy this post of mine from ten years ago. (I’ve been banging away at this for a while now.)

    (In the comment-thread to that post you’ll also get a glimpse of a gadfly, The One Eyed Man, who used to be a regular commenter here.)

    Posted May 19, 2024 at 7:51 pm | Permalink
  10. Jason says

    Thanks Malcolm for the link. I’ve actually looked at some of your earlier posts before. It’s too bad the one eyed man doesn’t comment anymore-your droll and caustic exchanges with him are so splendid.

    Posted May 19, 2024 at 8:01 pm | Permalink
  11. Malcolm says

    He’s an old friend, intelligent, and a great guy, but he was terribly exhausting to argue with (and not in a good way: when it’s productive, both sides learn something from each other, which never happened). The linked thread is a good example, if much shorter than some of our more wearisome exchanges.

    Posted May 19, 2024 at 8:03 pm | Permalink
  12. Malcolm says

    Jason,

    It’s too bad the one eyed man doesn’t comment anymore…

    Well, if he sees your review, he might be encouraged to do so. (Not sure if he still reads the blog; we’ve been out of touch for a few years.)

    I’m fine with things as they are: you can’t have productive arguments if you have no premises in common. It can get in the way of what is otherwise a good (and long-standing) friendship.

    Posted May 19, 2024 at 8:07 pm | Permalink
  13. Autisticus Spasticus says

    The psychological mythology of America is based on Calvinist ethics; that the soul is free to choose. “Common grace” is a Protestant concept which refers to the grace of the mythical god of the Semites, which is supposedly common to all humanity, and is limited only by unnecessary cultural factors. It is “common” because its benefits are experienced by, or intended for, the entire human race, without distinction between one person and another; and it is “grace” because, according to this Reformed thinking of 19th and 20th century Calvinists, it is unmerited and sovereignly bestowed by god.

    Naturally, the desperate rationalisations with regard to evolutionary inequalities are expressed at a purely secular level. But once we move out of countries submerged in the Christian (and Protestant in particular) yolk, people no longer suffer from this “ogre of the superego” as far as evolutionary inequalities are concerned. These are the most radioactive topics in academia, but only because the West gazes at its cultural navel. In countries that are not tainted by Christianity, the taboo disappears completely. The Chinese, for example, not only expel Muslims and discriminate against blacks, but are free to study and practice eugenics without any guilt whatsoever.

    Posted May 20, 2024 at 4:32 pm | Permalink
  14. Of course sex is binary; because the whole point, at its simplest, is to mix genes from two different individuals. Instead of offspring being, aside from mutation, identical to the parent; which is how asexual reproduction works. With sexual reproduction there is much more diversity; with humans chromosomal pairing alone allows for over a quarter-million genetically distinct possible offspring. It’s completely unnecessary to have the mating complexities of three or more sexes to produce offspring. How different the two sexes are in each species depends on mating and offspring rearing strategies. We should be thankful our strategy is not like the ants or salmon.

    Posted July 2, 2024 at 6:24 pm | Permalink

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