The video below, highlighted on Everyday Feminism, came with a few words on the website:

“Yes, trans women are women, but they’re still biologically male.” Ever thought or said something like this? You might even have good intentions by stating what you think is a simple fact – after all, gender is a social construct, while sex is biological, right? Actually, this “simple fact” of trans women being “biologically male” is inaccurate – and this misrepresentation of the truth is being used to justify some pretty hateful things. So if you really want the facts, and to follow through on your good intentions by being a good ally, check out Riley J. Dennis’ explanation of why trans women are not biologically male. With Love,

The Editors at Everyday Feminism

Well, I’d like to be a good ally, but not by denying the truth. And, in fact, sex is indeed biological—not a social construct like gender. But biology doesn’t give us a reason to discriminate against trans people, for discrimination is a moral issue, and can’t be decided by biology alone.

We’ve all heard the mantra that gender is a social construct, which I take to mean that what gender you claim to be, or feel you are, should be based solely on your own perception, and will gain credence from social agreement. (Let me add, though, that some transgenderism may have a biological basis: a neurological or physiological situation that makes you feel that you don’t belong to your “assigned sex”.)

And I’m willing to agree to gender as a social construct; if someone was born biologically male but feels female, or vice versa, I’m perfectly willing to go along with that, though of course many feminists disagree (and I’ll leave them to argue it out), as do conservatives who don’t want those people going to the “wrong” restrooms. (I don’t give a rat’s patootie which bathroom they use.)

But the 7½-minute video below, by Riley J. Dennis, identified as “non-binary trans woman, writer, YouTuber, activist, and educator,” claims more: that sex itself is a social construct. That is, she claims that whether you are male or female as a condition at birth is not a biological phenomenon, but a social construct. This claim, which is insupportable if you know anything about biology, is made for one reason only: because, as the Everyday Feminism article notes, it supposedly “justifies some pretty hateful things.” As Dennis says, “Trans women are not male, and saying that they are allows some people to justify the mistreatment of trans people.”

Here, then, we have someone trying to distort the biological evidence in service of an ideological agenda. While I’m in sympathy with that agenda, I’m not sympathetic to the claim that sex itself is a social construct. Were that true, we’d have to revise hundreds of years of biology, and not just in humans. What we should do is accept the facts of biology, as well as the fact that some people feel that they’re not members of their biological sex, and then construct our social mores based on these facts—without distorting the biology.

Let me first say that if you examine newborn humans, a very small fraction won’t be assignable unambiguously to “male” or “female” based on genitalia, or even chromosomes. Sometimes “intersex” infants have ambiguous genitalia, or even both forms, and there are also XXY and XO babies who show intermediate traits. But these are extremely rare. For all practical purposes, as we know well, newborns fall neatly into the classes of “biologically male” and “biologically female”. This is similar to virtually all other animals. I have, for instance, looked at millions of fruit flies, and while there are a very few whose sex is ambiguous, I’d say those are fewer than one in several thousand. (Sex in flies is taken as a biological fact, not a social construct.) What we have in humans, as in other species, is a strong bimodality of sex with a very low frequency of ambiguous cases forming a deep valley between the male and female peaks. Although Dennis says that “sex isn’t a perfect binary,” it’s pretty damn close to perfect in separating people into two groups.

Here’s Dennis’s claim, which I quote verbatim:

I would argue that sex needs to go through the same change that gender has already gone through. It’s not a static fact; it’s a social construct. . . Sex is not a biological fact because it is determined by things that are largely changeable [by medical intervention], and the only part of it that is unchangeable [chromosomal constitution] doesn’t have any real-world effect. So it is just as much a social construct as gender is. . . Biological sex has to undergo the same paradigm shift that gender did. We have to start thinking of that as a social construct rather than as an inarguable fact.”

and the reason for this claim follows immediately:

Because when people say that a trans woman is “biologically male,” they use that as a way to attack trans people. They use it as an excuse to exclude us from bathrooms, locker rooms, and other women’s spaces.

It’s curious but telling that Dennis argues almost entirely about trans women, ignoring trans men. But that’s probably because she’s trying to defend her own gender more than the concept of transgenderism in general. Regardless, her argument is one based on wish-thinking and ideology rather than biology.

Why does Dennis argue that sex itself is a social construct? The argument is thin and weak. She argues that biological sex is based on a combination of traits, to wit:

1.) chromosomes (in humans, XY is male, XX female)

2.) genitals (penis vs. vagina)

3.) gonads (testes vs. ovaries)

4.) hormones (males have higher relative levels of testosterone than women, while women have higher levels of estrogen)

5.) secondary sex characteristics that aren’t connected with the reproductive system but distinguish the sexes, and usually appear at puberty (breasts, facial hair, size of larynx, subcutaneous fat, etc.)

I will maintain that using genitals and gonads alone, more than 99.9% of people fall into two nonoverlapping classes—male and female—and the other traits are almost always coincident with these. If you did a principal components analysis using the combination of all five traits, you’d find two widely separated clusters with very few people in between. Those clusters are biological realities, just as horses and donkeys are biological realities, even though they can produce hybrids (sterile mules) that fall morphologically in between.

Dennis’s argument against these indicators of sex are as follows:

Chromosomes aren’t usually tested, so people don’t usually know their chromosomal constitution. So what? You’re either XX, XY, or, rarely, something else, and it’s not hard to determine this. Against this, Dennis argues that sex isn’t defined entirely by chromosomes (well, it is by many biologists), and, even so, “What good does dividing people based on their chromosomes do?”

To that I’d respond, “chromosomes are correlated with a lot of other traits (that’s because they genetically produce those traits)—traits that we’ve evolved to respond to differentially. In general, someone who is XY will be attracted to someone who is XX, and that’s based on secondary sex characteristics that themselves are induced by chromosomes. Yes, there are people who are homosexual or bisexual (yet still identify as “male” or “female”), but if sex were purely a social construct, sexual selection wouldn’t work: males would look identical to females. That difference itself suggests that there’s a biological reality to sex, and that this biological reality—the correlation of chromosomal constitution with reproductive traits and with secondary sexual traits—is what has caused both behavioral and morphological differences between the sexes. If sex were purely a social construct, as Dennis says, then male deer wouldn’t have antlers, male peacocks wouldn’t have long tails, human females wouldn’t have breasts, and human males wouldn’t have greater muscle mass and upper body strength.

Hormones “aren’t visible without a test.” Again, you can make them visible with a test. Dennis argues that hormones can be altered by doctors, but that’s a recent cultural innovation that doesn’t affect my argument for sex based on chromosomal constitution that produces marked differences in the other characters. Remember: the chromosomal constitution itself, once inherited, sets off a string of genetic changes that ultimately lead to differences in the other four sets of traits.

Genitals and gonads “usually aren’t visible most of the time.” Well, not when they’re covered by clothing, and ovaries are on the inside, but that’s fatuous. Inspection of genitals and gonads will tell whether they conform to the peaks of the bimodal distribution or are rare exceptions. Dennis argues further that genitals can be changed with surgery, which is true, but that is simply a human alteration of biological sex, and those alterations are of course easily detectable. Likewise with her argument that gonads and testes can be removed when diseased, effacing an identifier of sex. But that happens later, and of course doesn’t change the chromosomes. And it didn’t happen at all before surgery came around in the last 0.005% of the span of human evolution.

Secondary sex characteristics, says Dennis, appear only after puberty, as if that’s some argument against their reality. But that’s irrelevant, for puberty is itself a biological phenomenon. Dennis adds that there is variation in these traits: they are not “perfect differentiators of sex.” Some males, for instance, develop little or no facial hair, and some women have facial hair. She also argues that some “people with vaginas” (a euphemism she uses for “woman”) develop small breasts, and some develop large breasts, but that “neither of those is more or less female”. Again, this is irrelevant to the argument against the reality of sex, for even considering fatty breasts alone, the presence of that one trait is a very good indicator of biological sex.

Dennis also argues that secondary sex characteristics militate against biological sex because “they can be changed through hormones or surgery.” But that’s again irrelevant to the argument from biological sex as a reality at birth. I could use lasers to remove the sex combs of Drosophila males (stiff tufts of bristles on the forelegs that males use to grasp females during copulation), but that doesn’t mean that sex in Drosophila is a social construct. Similarly, you can dye a female cardinal bright red to resemble a male (a secondary sexual characteristic), but that says nothing about whether sex in cardinals is a social construct. It can’t be, because cardinals don’t even have a society.

The culturally-induced malleability of biological traits does not mean that those traits aren’t real but merely social constructs; it just means that those traits can be artificially changed to resemble those of the other sex.

Dennis concludes that of the five traits listed above, four of them can’t be used to “accurately determine sex.”(Chromosomes seem to be the exception.) Well, yes, but they are accurate nearly all the time, and when combined are accurate virtually all of the time. There are of course exceptions, but as I said, they’re very rare.

Can we not accept the fact that sex is indeed a biological phenomenon, while someone can still choose to accept a gender that doesn’t correspond to their biological sex? The concept of biological sex has been extremely useful in biology—it’s a linchpin of a ton of research in evolutionary biology and other fields, and, with very few nonclassifiable cases, it’s an objective reality.

Accepting that truth may indeed give some people ammunition to discriminate against trans people, but the cure for that is not to deny biological reality: it’s to create more empathy so that trans people aren’t the victims of discrimination. Those who use the reality of biological sex to marginalize trans people are committing the naturalistic fallacy: claiming that an “ought” follows from an “is”.