The Social Construction of Sex: A Formal Argument


Everywhere nowadays there seems to be what some are calling the denial of common sense: the argument that sex is socially constructed, or made up by social practices. Arguments from J. K. Rowling and a seemingly endless armada of right-wing provocateurs have spread the message that this is woke nonsense and yet another attempt of the left’s attempt to reimagine everything. This, in turn, has led my students to question my teaching of this subject. They simply don’t accept social constructionism as a theory and dismiss it without due consideration as an “agenda”. So, in this post, I am going to create a tedious but hopefully brief argument showing why philosophers and many other scholars and scientists believe that sex is socially constructed and not biologically determined.

The Deductive Arguments

The formal arguments are comprised of two deductive arguments and a series of inductive ones. The first deductive argument is a modus ponens type that goes like this:

  1. If sex is not biologically determined, then it is socially constructed.
  2. Sex is not biologically determined.
  3. Therefore, sex is socially constructed.

The first thing to note about this argument is that it isn’t so much an argument for the social construction of sex, as it is an argument against the biological determination of the same. The second thing to note is that this first premise is perhaps the weakest assumption of my whole argument. It is assumed that if no biological determination can be made that the best remaining explanation for the concept of “sex” is a social one. As there remains the possibility of a third alternative, this can only be as good as whatever the alternatives are. But most likely this argument’s opponents would challenge the second premise, so we need a second argument to support it, such as follows:

  1. If sex is biologically determined, then there must exist at least one definitive biological attribute which all members of that sex possess and no non-members of that sex possess.
  2. No biological attribute can be found that satisfies both criteria.
  3. Therefore, sex is not biologically determined. 

This Modus Tollens argument starts by simply defining the meaning of “biological determination” as having some biological attribute that can distinguish all members of one sex from all non-members. The second premise assumes that no attribute which would satisfy the logical requirements necessary to serve as the defining element exists, and so the argument concludes that sex cannot be biologically determined. Again, the second premise stands in need of support. The only reasonable way to justify this claim is with a series of arguments establishing counter-examples to any and all proposed biological attributes that presume to determine sex.

The Inductive Arguments

It would be impossible to refute every would-be contender, not because it couldn’t be done, but because it would take an infinite amount of time to do so. Rather then, let us first see if we can narrow the field of contenders. We know abductively that a successful biological attribute cannot be shared by multiple sexes, nor can there be any member of a sex who fails to possess the definitive attribute. Suppose “having arms” is taken to be the definitive biological attribute for the female sex and we can easily see how it would fail both criteria: there are some females who do not have arms and some non-females who do have arms. We don’t need both to fail however, either the one or the other failure would be sufficient to rule out whatever supposed attribute as a distinguishing attribute and so fail to establish biological determinacy. It should also be noted that no criteria could be an average since averages are by definition social and not biological attributes. For example, it would be impossible to claim that females are humans that are “shorter on average” than other sexes since we are looking for a way to determine an individual’s sex. No individual is the average, even if they happen to be the mean, the mode, or the median of some human attribute.

Most proponents of biologically determined sex argue one of four major categories: gender, anatomy, physiognomy, or genetics. It is, of course, possible that there are other potentials candidates that would meet the criteria, but if so, I have never encountered them, and as the burden of establishing such claims must rest with the proponents of the theory that believes that they exist, I will leave it to them to bring up in rebuttal. In what remains, I will argue that a counter-example can be produced for each potential attribute of the four categories, dealing with many though certainly not all possibilities as examples.


Gender would include particular behaviors or appearances that we could say define sex, e.g., females are the humans who wear their hair long. There are obviously many examples of gender that could work such as males are the ones who wear pants or grow beards or earn an income, while females are the ones who wear dresses or make-up or take care of the children.

All of these examples and indeed any you can probably think of could have an exception. To establish them as the defining biological attribute, we would have to prove that all males have beards, including young ones, or have ever had “long” hair or that no female has ever worn pants or neglected their children. Even a single example of a single instance of this would be sufficient to disqualify it as a defining biological attribute and even a hypothetical example would do the same, since to be distinguishing, it cannot be possible to show a counter-example.

All of these examples can be proven inductively false, and so none can establish biologically determined sex. Such is true of any gender act or appearance we wish to use.


Anatomy includes the physical parts a person possesses that we could say define sex, e.g., females are the humans who possess uteruses or ovaries or breasts. Or males are the humans who possess penises or testicles or Adam’s apples. For these, or other, examples to establish biological determinacy we would have to prove that no men have uteruses and all women have them, including those who have had a hysterectomy. That a human who lost their penis was no longer a male, even if that didn’t quite make them a female. In fact, it’s easy to imagine that whatever organ we designate as the definitive one, could be removed.

Now we could simply hardline on this point and say that it is indeed the penis that makes a human male, and were a male to lose his penis he could not be classified as male anymore, and while not female, we could make up a new category for such people. However, there are two problems with doing this and still claiming that sex is biologically determined. First, the very act of inventing new sexes seems to suggest social construction, but we could defend against this by claiming that we are not “inventing” but discovering as many new biological sexes as we need to fit everyone in. While problematic in other ways, the more difficult problem for those who wish to establish biological determinacy for sex is that, by definition, it would prove sexual transition is not only biologically possible but extremely common-place, as the male who loses his penis transitions to a new sex and if their penis is regrafted to their body would allow them to transition back to male. In the same way, a female could have a penis attached and could then, by definition, become a biologically determined male. This is a conclusion that I take those who wish to establish biological determinacy for sex want to avoid.


Physiognomy includes biological functions of organs or organisms that we could say define sex, e.g., females are the humans who can bear children or males are the humans who can produce sperm or impregnate a female.

For these examples to establish biological determinacy, we would have to prove that no male can bear children and that all females can bear children. Any sterile human could not be considered female, and neither could those who have yet to prove they are not sterile, such as children. Similarly, a human whose testicles fail to produce sperm could not be considered a male, whether they were born with those testicles or they are made of plastic would make no difference.

We might think that combining physiognomy and anatomy would strengthen the case for biological determinacy, but in fact, it would weaken it because now it would be harder to prove there are no exceptions since we have multiple criteria to satisfy, any one of which could provide an exception. Ultimately sex cannot be established on the basis of the function of organs because organs can change, as with anatomy, but also because they can functionally fail.


Genetics includes the chromosomal characteristics a person possesses, i.e., their genes, that could define sex, e.g., females are humans who have two X chromosomes or males are the humans who have an X and a Y chromosome. For these examples to establish biological determinacy, we would have to argue that no men have anything other than an X and a Y chromosome and that no females have anything other than two X chromosomes. Both of these are inductively false. There is much larger genetic diversity than is commonly understood, including chromosomal sequences of XXX, XXY, XYY, XXXXX, XXXXXXX, and more. Additionally, there are genetically related conditions, such as androgen insensitivity, where humans who possess XY chromosomes are born with functioning vulvas, uteruses, and breasts, everything except the ova.


One, ill-conceived way of trying to save the biological determination theory is to dismiss these as mere exceptions to the general rule of binary biological sex. The problem with this idea is two-fold. One problem is logical. As I showed above, it only takes one counter-example to undo the theory. The second problem is more profound, in that it seems to accept, at least methodologically, the idea of social construction prior to biological determination. If exceptions can be ignored, then we are not so much dealing with defining sex by a biological attribute but rather with socially constructing a biological attribute that we arbitrarily commit to. This kind of biological determination is a social construction, one step removed.


History might serve as another possible source of determinacy for sex. Some may argue that the sex “you are born with” is your “true” sex. At first, it may seem plausible, but yet again we find that this sort of argument assumes a social construction rather than a biological determination. To claim a child is assigned a sex at birth by the arbitrary application of some biological attribute, either by a parent or a doctor is merely to claim this authority is the rightful one to choose. The idea that sex is chosen is assumed.

But there is literally no reason why this arbitrary choice must remain permanent or why a parent’s choice should supersede the individual’s. To analogize, it’s no different than claiming a person cannot change their name because it was assigned to them at birth by their parents. If that were the case then no married woman could take her husband’s last name, because she was born with her maiden one. Obviously, this is not true. In point of fact, we allow people to change their names, precisely because it was an arbitrary decision on the part of a person’s parents and we generally hold that individuals may decide for themselves arbitrary choices regarding their identity.

Socially Constructed Sex

None of this is to suggest that things like anatomy, genetics, and physiognomy or our history have nothing whatsoever to do with the determination of sex, only that the choice of which to focus on is seemingly always just that, a choice someone is making. You or someone else is always choosing your sex. When you meet a stranger, they take a guess. You either agree with their determination or you do not. What a theory of socially constructed sex really is then is a commitment to allowing individuals to decide on what basis they would prefer their sex to be determined. And, upon realizing they have the power to make this choice, most people base it on how they feel about themselves. This internal feeling is arguably just as biological an attribute as any other we have so far considered. The point here is not what they choose based on, but that they are the most appropriate person, and perhaps the only person, capable of making that choice.

Those who would like to be the dictators of others’ sexuality or those who would prefer to defer their choice to others, sometimes like to hide behind the bulwark of objective fact or science, but no such epistemological territory exists as this argument hoped to show. Without the claim of objective fact, such assertions have been revealed to be merely the wishes of people who like to tell others who they can and can’t be. Social constructionism asserts that freedom of sexuality is always chosen and trans people, like cis people everywhere, simply demand that others respect their choice about themselves.