Oh, they do know - but it’s currently politically impossible for anyone other than the most fearless of iconoclast to say, as to declare oneself critical of innate gender identity being both real and far more socially significant than biological sex is possibly the worst heresy anyone can commit on social media at the moment.
What actually happend is the break up of over archaic role models and scientific progress.
Some people today, have a decent answer to that question.
With "female brain structure" i mean traits that are commonly overrepresented in what you might see as a regular woman. I know its inaccurate but so is the opposite, by saying there are only 2 genders and men are all men. Gender is a spectrum in many dimensions and my example of male physique and female brain structure is just a simple counter example against this.
What does this mean? Are you talking about gender or sex?