Since I first heard that “gender is a social construct” I’ve done some light reading on the topic to see what the actual science is, but no definitive answer has been given. Biological sex is a fact and well defined in literature on biology. Gender is defined as “the behavioral, cultural, or psychological traits typically associated with one sex”  as biology defines sex as being binary and follows purely physical traits. Gender on the other hand, is not strictly defined as being purely about the physical, as it includes behavioral and psychological traits that have social influences, and culture which is an entirely social phenomenon.
In our societies we have legislation that does deign some behaviors unlawful. We punish unlawful behavior with legal sanctions such as prison or fines. Whether or not a behavior is in truth unlawful depends both on the behavior and the subject context. For instance, someone can be declared not competent to stand trial, as a result of among other things mental illness. In this case, we are saying that the behavior was unlawful, yet the personal biological/medical circumstances of the person who committed the crime, are such that it cannot be punished.
We could say that our justice system is based on people being actors, that are able to tell lawful behavior from unlawful. Thus, we create axiom 1: Able to tell lawful behavior from unlawful behavior.
Secondly, we have to consider which behaviors could be deemed unlawful. Can something that is biological be illegal? This goes towards the human construct of government and by extension law, versus the reality of biology. Of course, we have cases of genetics such as the warrior genes, that may make someone more likely to be violent, however as long as they can tell lawful from unlawful behavior, this is not a recognized legal defense.
So from this we can create 2 principles for making something illegal:
A) People have to be able to tell what is legal and what is not legal. (Competency)
B) One cannot legislate against biology.
The basic argument presented to make homosexuality no longer unlawful behavior was as follows:
Premise 1: You cannot make something biological illegal.
Premise 2: Homosexuality is biological
Conclusion:Therefore, you cannot make homosexuality illegal.
This is a logically valid argument. Premise 1 is widely accepted in legal circles, both in terms of principles but also in terms of practice. Premise 2 is contested, but the science is starting to come in on the topic. What homosexuality is, is the attraction to someone sharing your biological sex. If homosexuality is genetic/biological then it follows that who you are attracted to is hardwired in your brain. In terms of economics we could argue that what sex you are attracted to is the “need” and your preferences in a partner is the “want”. In the same way that need is “thirst” but your preference for a drink is Miller Lite.
Feminism has long claimed that there is no such thing as male or female brains. That despite the differing hormonal cocktails we receive throughout pregnancy and life, in addition to differing chromosomes this does not influence the functionality of the brain.    Which brings an interesting contradiction. If there is no such thing as male or female brains, then how can someone be born as “the wrong gender”? After all, trans is rapidly becoming the new gay, and the basic premise of trans is “being born as male and identifying as female” or “being born as female and identifying as male“.
If I put this in the form of a syllogism:
Premise 1: Gender is a social construct
Premise 2: People can be born as the wrong gender
Conclusion: Therefore, people can be born as the wrong social construct.
This is a logically valid argument, but the conclusion does not make sense. If you are born as something, then it is biological, this follows from the fact that social construct cannot come into play until you exist within a social group. Secondly, if gender is a social construct, then you are not born as a gender, you develop into it as a result of social interaction. If I restructure the syllogism:
Premise 1: Sex is biological.
Premise 2: People can be born with the wrong sex.
Conclusion: Therefore, trans is biological.
This argument works in terms of validity. Premise 1 is uncontroversial, however, there is little proof for premise 2.
Our self-perception must come from the brain, as it is the only organ in our body that has the capability to process information in the manner required to construct your self-image.
The trouble really arrives when you try to keep all these 3 positions in your mind at once.
The conclusion to the homosexuality-principle “What sex you are attracted to” is biological.
The conclusion to the transgender-principle “What sex you identify as” is biological.
The conclusion to the feminist-principle “There are no biological sex differences in the brain”.
I outlined the reason why there is an incentive to make both homosexuality and transgender biological from the perspective of advocates for both groups. If something is biologically contingent, then discrimination against it, would be violating basic human rights as it puts it in the same category as race.
Feminism on the other hand has a very strong incentive to make everything related to gender a social construct, because if it is not, then the convergent evolution of similar gender-roles within a disparate group of cultures indicates the superiority from an evolutionary perspective of the current status quo. Furthermore, rather than the oppressive thumb of the patriarchy oppressing the feminine sex for all of history, the current status is a result of individual choice on an aggregate level over a long period of time.
After all, if gender roles are the result of biology which drives choices made by men and women, then it follows that working to “make things equal” is undermining the very choices made by both women and men in the first place. This is where concepts such as “internalized patriarchy” become very insulting to women, by implying that a woman who has made choices that do not fit within the permitted choices outlined by feminism, is not doing so because she is in fact a strong, independent woman, but because she is brainwashed. To construct yet another syllogism:
Premise 1: You are attracted to a sex.
Premise 2: You identify as a sex.
Premise 3: There is no such thing as biological sex.
Premise 4: Sex is a social construct
Conclusion A: Therefore, the sex you are attracted to is a social construct. (From 1, 3, 4)
Conclusion B: Therefore, the sex you identify as is a social construct (from 2, 3, 4)
The questionable premises here are 3 and 4 in terms of soundness, but the argument is valid. If I restructure as:
Premise 1: You are attracted to a sex
Premise 2: You identify as a sex
Premise 3: Sex is biological
Conclusion: Therefore, the sex you are attracted to, and the sex you identify as are biological
I don’t think a single one of those premises are hotly contested in science, and the argument is valid.
The takeaway from this diatribe is that feminism in it’s rush to stay relevant through intersectionality, has become a religion where the basic premises end up in a form of Kettle Logic where the whole system of thought falls apart because it is built on contradictory premises. I’ll demonstrate why:
If sex is biological, then it follows that certain behaviors are biological as well. Such as women being more inclined by nature to take care of children. If women are more inclined by nature to take care of children, it follows that behaviors that would result in more successful child-rearing would be selected for by evolution.
From a perspective of mathematics:
If you have 2 women, one has an 80% chance of successfully raising a child to reproductive age, the other 50%.
Both women are identical in every other way.
They become capable of pregnancy at 16, and become unable to have children by age 45. (29 reproductive years) At 1 child pr year, this is a total of 29 children, out of which the 50% mom will raise 14 – 15, and the 80% mom will raise 23 – 24. In one generation, mom-80% had 12 daughters who inherit her gene for successful child-rearing, and mom-50% had 7. In generation 2, the 12 go on to have a total of 278 children, 139 of which inherit her successful gene. In the second generation mom-50% has 7 daughters who have 101 daughters inhering her gene. Over a few hundred this compounds to the point where the 80% gene is in most of the female population.
Some would be inclined to dismiss this argument as “biological determinism” but that isn’t really the case. The core premise of evolution by natural selection is that organisms that adapt the best to their circumstances survive and reproduce, whereas organisms that do not adapt, die out. For something to be deterministic, it would indicate having no choice in how your life played out. In essence, by knowing someone’s genetics, we would be able to tell exactly how their life will play out. The argument is that over the span of hundreds of generations, certain behaviors and the genes that influence them have been much more successful in the survive and reproduce game than other genes. Therefore, these genes are now present in a very high proportion of the population, and therefore lead to successful behaviors being widespread within a population.
The “biological determinism” accusation is frequently a false dichotomy where arguments from biology is pitted against the debunked “Blank slate” hypothesis.
The core of this essay, is that you cannot on one end argue that gender is a social construct, while holding the position that both what gender you are attracted to, and what gender you perceive yourself as are biological. This becomes a contradiction. Gender is by definition the manifestation of behaviors, cultural or psychological traits associated with one sex.