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26 July 2023

Why biological sex matters

Some argue that lived experience and personal choice trump biology – but they are wrong.

By Richard Dawkins

Note: We asked two thinkers to address one of the most vexed questions of our time: “What is a woman?”
Here, Richard Dawkins argues that biological sex represents a “true binary”. See here for Jacqueline Rose on why that binary should be challenged.

In 2011, I was invited to guest edit the Christmas double issue of the New Statesman. I enjoyed the experience, which involved a visit to Christopher Hitchens in Texas to conduct what turned out to be his last interview. I didn’t ask him, “What is a woman?” In 2011, it wouldn’t have occurred to anyone to ask such a daft question. Today it is hurled at embarrassed and perplexed politicians, in tones that are challenging to the point of belligerence. It isn’t hard to imagine Hitchens’ response if he could be asked it today.

My main contribution to that Christmas issue was a long essay on “The tyranny of the discontinuous mind”. Everywhere you look, smooth continua are gratuitously carved into discrete categories. Social scientists count how many people lie below “the poverty line”, as though there really were a boundary, instead of a continuum measured in real income. “Pro-life” and pro-choice advocates fret about the moment in embryology when personhood begins, instead of recognising the reality, which is a smooth ascent from zygotehood. An American might be called “black”, even if seven eighths of his ancestors were white.

[See also: Apes with big brains: Richard Dawkins on what makes us human]

Anthropologists quarrel over whether a fossil is late Homo erectus or early Homo sapiens. But it is of the very nature of evolution that there must be a continuous sequence of intermediates. You can vote on your 18th birthday but not before, as though the stroke of midnight signals a quantum leap in your political competence. Universities award first-, upper second-, lower second- and third-class degrees, even though everyone knows that the top of any one class is much further from the bottom of the same class than it is from the bottom of the class above. There are Oxford dons with faith in something they call “the alpha mind”, a Platonic “ideal form”, like a perfect triangle hanging pristine and aloof above messy reality.

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If the editor had challenged me to come up with examples where the discontinuous mind really does get it right, I’d have struggled. Tall vs short, fat vs thin, strong vs weak, fast vs slow, old vs young, drunk vs sober, safe vs unsafe, even guilty vs not guilty: these are the ends of continuous if not always bell-shaped distributions. As a biologist, the only strongly discontinuous binary I can think of has weirdly become violently controversial. It is sex: male vs female. You can be cancelled, vilified, even physically threatened if you dare to suggest that an adult human must be either man or woman. But it is true; for once, the discontinuous mind is right. And the tyranny comes from the other direction, as that brave hero JK Rowling could testify.

Sex is a true binary. It all started with the evolution of anisogamy – sexual reproduction where the gametes are of two discontinuous sizes: macrogametes or eggs, and microgametes or sperm. The difference is huge. You could pack 15,000 sperm into one human egg. When two individuals jointly invest in a baby, and one invests 15,000 times as much as the other, you might say that she (see how pronouns creep in unannounced) has made a greater commitment to the partnership.

Anisogamy is the rule in most animals, but it hasn’t always been so. Some primitive animals and plants are still “isogamous”: instead of macrogametes and microgametes, they have medium-sized (iso)gametes. Both partners contribute equally to the joint investment. To make a viable zygote you need the sum of two isogametes, each worth half a zygote. The same requisite sum can be achieved if one partner contributes a slightly smaller isogamete, but this will work only if the other partner chips in with a larger isogamete to redress the shortfall. You could say the minority investor is exploiting the partner who commits the larger gamete.

You can perhaps see where this argument is going, and it has indeed been modelled mathematically. Isogamy is unstable. Under plausible conditions, we get runaway evolution towards some individuals making smaller and smaller gametes, while others go in the other direction, making larger and larger gametes. At the end of the runaway, we now have microgametes that actively seek out macrogametes, and they evolve wriggling tails to propel their pursuit. Macrogametes are in demand, and have no need to go out looking for microgametes. Because microgametes are so small, individuals who make them can afford to make many. Macrogametes have to be few because, as economists love to say, there’s no such thing as a free lunch. The imbalance also means that microgamete producers (“he/him”) can mate with lots of different macrogamete producers (“she/her”), deserting each one in turn. Or they can sequester for themselves a harem of she/hers. There’d be no point in a she/her gathering a harem of he/hims around her: she doesn’t have enough macrogametes to benefit.

The anisogamy binary furnishes the oldest and deepest way to distinguish the sexes. There are others, but they are less universally applicable. In mammals and birds, you can do it with chromosomes. Each body cell of a normal human has 46 chromosomes, 23 from each parent. Among these are two sex chromosomes, called X or Y, one from each parent. Females have two Xs, males one X and one Y. Any mammal with a Y chromosome will develop as a male. When a male makes sperm (“haploid”, having only one set of 23 chromosomes), 50 per cent of them are Y sperm, destined to beget sons, and 50 per cent are X sperm, which make daughters. Birds and butterflies have a similar system, but the other way around. It is females that have XY, except that they’re called ZW. In flies, the equivalent of the Y chromosome is a zero. If a fly has two sex chromosomes she’s female. A fly with only one sex chromosome is male. Many reptiles use temperature instead of chromosomes. Turtles that are incubated below 27.7°C develop as male, warmer eggs as female.

Clownfish determine sex not by temperature but by dominance. All but one of the members of a group are male, and like many animals they sort themselves into a dominance hierarchy. There is only one female in the group. When she dies, the dominant male changes sex and becomes the female. What this means in gametic terms is that his testes shrink and ovaries grow instead. The principle of binary sex at the level of micro- and macro-gametes is maintained. Hermaphrodites such as earthworms and land snails have testes and ovaries all in the same body at the same time. Snails are capable of exchanging sperm both ways, having first violently fired harpoons into each other. Angler fish also have both male and female organs in the same body. But it comes about in a curious way. Males are diminutive dwarves; they locate a female, sink their jaws into her body wall, and then become part of her as no more than a tiny testicular excrescence.

In mammals, including humans, there are occasional intersexes. Babies can be born with ambiguous genitalia. These cases are rare. The highest estimate, 1.7 per cent of the population, comes from the US biologist Anne Fausto-Sterling. But she inflated her estimate hugely by including Klinefelter and Turner syndromes, neither of which are true intersexes. Klinefelter individuals have an extra X chromosome (XXY) but their Y chromosome ensures that they are obvious males, producing microgametes, albeit from reduced testes. Turner individuals are unambiguous females with no Y chromosome and only one (functioning) X chromosome. They have a vagina and uterus, and their ovaries, if any, are non-functional. Obviously, Klinefelter (always male) and Turner (always female) individuals must be eliminated from counts of intersexes, in which case Fausto-Sterling’s estimate shrinks from 1.7 per cent to less than 0.02 per cent. Genuine intersexes are way too rare to challenge the statement that sex is binary. There are two sexes in mammals, and that’s that.

But what about gender? What is gender, and how many genders are there? It is now fashionable to use “gender” for what we might call fictive sex: a person’s “gender” is the sex to which they feel that they belong, as opposed to their biological sex. In this meaning, “genders” have proliferated wildly. When I last heard, there were 83. But that was yesterday. What does “gender” actually mean?

[See also: Rosie Duffield: “You never change sex”]

Language evolves, and many words change their meaning on a timescale of centuries. But “gender” has been fast-tracked. It is primarily a linguistic technical term. Linguists classify words of a given language according to such things as the suffixes on adjectives that qualify them, or their agreeing pronouns and articles. All French nouns follow either le or la. They take different pronouns, and adjectives agree with them in a gendered way (le chapeau blanc but la robe blanche). Normally (there are exceptions, such as la souris for a mouse of either sex) males are le and females la. This makes it convenient to use the label “masculine” for le words and “feminine” for la words. Table is a feminine word, but French speakers don’t think of a table as a female piece of furniture. It’s just a la word. Lithuanian also has two genders, but possessive pronouns agree with the gender of the possessor (as in English) whereas in French they agree with the gender of the object possessed. Estonian has only one gender, which I suppose means no gender – the very idea of gender is meaningless. Some Bantu languages such as Nyanja, the dominant language of my childhood home of Malawi, have many. Steven Pinker’s The Language Instinct quotes Kivunjo as having 16 genders. These are not 16 sexual identities, they are 16 families of nouns classified according to how verbs agree with them.

In English, as in French, gender and sex align. All female animals are of feminine gender, all males are masculine, all inanimate things are neuter (with whimsical exceptions such as ships and nations, which can be feminine). Because of the perfect correlation between sex and gender in English grammar, it was natural for English speakers to adopt “gender” as a genteel euphemism for sex: “Sam is of female gender” sounded more polite than “of female sex”.

Illustration by Cold War Steve

But that convention recently gave way to another one. The fashion for females to “identify as” male and for males to “identify as” female has emplaced an assertive new convention. Your genes and chromosomes may determine your sex, but your gender is whatever floats your boat: “I was assigned male at birth, but I identify as a woman.” Finally, the wheel turns full circle, and self-identification has now gone so far as to usurp even “sex”. A “woman” is defined as anyone who chooses to call herself a woman, and never mind if she has a penis and a hairy chest. And of course this entitles her to enter women’s changing rooms and athletic competitions. Why should she not? She is, after all, a woman, is she not? Deny it and you are a transphobic bigot.

High priests of postmodernism teach that lived experience and feelings trump science (which is just the mythology of a tribe of oppressive colonialists). Catholic (but not Protestant) theologians declare that consecrated wine actually becomes the blood of Christ. The dilute alcohol solution that remains in the chalice is but an Aristotelian “accidental”. The “whole substance” (hence the word “transubstantiation”) is divine blood in true reality. In the new religion of transsexual transubstantiation, a “woman’s penis” is just an “accidental”, a mere social construct. In “whole substance” she is a woman. A trans-substantiated woman.

Sarcasm aside, gender dysphoria is a real thing. Those who sincerely feel themselves born in the wrong body deserve sympathy and respect. I was convinced of this when I read Jan Morris’s moving memoir, Conundrum (1974). As what she called a “true transsexual”, she distanced herself from “the poor cast-aways of intersex, the misguided homosexuals, the transvestites, the psychotic exhibitionists, who tumble through this half-world like painted clowns, pitiful to others and often horrible to themselves”. Under “misguided” she might have added today’s unfortunate children who, latching on to a playground craze, find themselves eagerly affirmed by “supportive” teachers, and au courant doctors with knives and hormones. See Abigail Shrier’s Irreversible Damage: The Transgender Craze Seducing Our Daughters (2020); Kathleen Stock’s Material Girls: Why Reality Matters for Feminism (2021); and Helen Joyce’s Trans: When Ideology Meets Reality (2021). Many of us know people who choose to identify with the sex opposite to their biological reality. It is polite and friendly to call them by the name and pronouns that they prefer. They have a right to that respect and sympathy. Their militantly vocal supporters do not have a right to commandeer our words and impose idiosyncratic redefinitions on the rest of us. You have a right to your private lexicon, but you are not entitled to insist that we change our language to suit your whim. And you absolutely have no right to bully and intimidate those who follow common usage and biological reality in their usage of “woman” as honoured descriptor for half the population. A woman is an adult human female, free of Y chromosomes.

This article appears in our Summer Special

[See also: The gender binary is false – Jacqueline Rose]

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This article appears in the 26 Jul 2023 issue of the New Statesman, Summer Special