>It seems that a hormonal change (switching to estrogen, or testosterone) brings out many of the stereotypical behaviors and mental states of the associated gender. You're not wrong. They are temperament influencing "drugs." They definitely affect the brain. Also, acting like a woman (if you're a man) should rewire your brain. One of my buddies, who is a neuroscientist, talked about the chicken or the egg: were their brains like this before or did living the lifestyle cause their brains to rewire (neuroplasticity) to make it observable? Similar things apply to homosexuals: we can look at a brain and see what a homosexual male brain looks like (their brains light up when they see attractive men in the same way male brains light up when they see attractive women...meaning...they are legit and genuinely attracted to men).