I'd argue it's a little of both, really. Anyone denying some sort of innate gender qualities on a biological level when things like hormonal baths are being studied is disregarding an entire population of both cisgender and transgender people alike. Still, there is plenty to imprint on people. See: the gender stereotypes present in this thread.

Quote Originally Posted by Melichoir View Post
Humans are not binary when it comes sexes, but we are heavily bimodal - sex is a 'spectrum, but an extremely vast majority of the population are discernibly male and female genetically. This is the same for any other genetic variations that are not part of the average (which keep getting brought up.) Even those that do have genetic variances, most of those still display outward sex characteristics that are predominately Male or Female. The issue is framing, though. On one side of the argument, people are saying flat out there are only two sexes cause of Chromosomes. They are wrong, as intersex is a thing. The otherside, however, is playing up intersex and other genetic outliers in a fashion to say "Sex is a spectrum so saying male and female is irrelevant." This is disingenuous (and wrong) as it seeks to muddy the water by implying a false truth with facts taken out of context. The false truth being that there is no such thing as two predominant sexes and that everything is interchangeable.
I don't think anyone is disagreeing with that. The issue is people outright denying both a. the existence of variations, and b. that sex/gender is a lot more complicated than what was taught several decades ago.