In comparing genetic propensities for illness or eye color with all human behavior, one is mixing physical predispositions without any choice for the individual having them, with predisposition that can include choice for humans, which is why included in the Torah is the human predisposition for adultery, theft, coveting, blasphemy, murder, homosexuality- thou shalt not. Teddy Roosevelt did not choose his youthful asthma, but did choose to overcome his predisposition to weakness and by effort became a brave man. I myself have overcome by choice many obstacles and weaknesses (without much help, as my own issues had no names when I was young), to become the man and artist I hoped to be.
I think we are confusing extremes and degrees. One cannot make oneself as tall and muscular as Charlton Heston if one is born a dwarf. But if one is born a skinny asthmatic type like Teddy Roosevelt, or a physical coward like Norman Mailer said he was, he can overcome it by acts of courage, and boxing in the ring. Or if a girl is born rather homely and fat, she can diet and work out and dress nicely, apply a bit of makeup and smile to become attractive. Predisposition does not completely determine our fate, whereas choice does. I was an extremely shy and quiet introvert as a youth, and couldn’t even work up the courage to get a date (while burning inside), so one day I decided to change, and forced myself to become an extrovert and thus mastered the art of getting girls. But it was not easy to change (now I am an extroverted introvert).
My point is, in that if one is born with a male body (physiology), then one must choose to develop that received raw material in a meaningful way of becoming a man, which means seeking to identify with the help of healthy male role models (hopefully a father, and brothers, friends, and sometimes a national hero or actor), and the same being for one born physiologically female. But today’s sick western society, with a plague of broken families and unfaithful fatherless and Godless homes, rampant pornography, abortion (the choice to destroy another’s body), and decline in moral restraints, has become so lost in chaos that it is now being accepted and promoted as ‘normal’ for a child to decide that he or she is a she or he, no matter what the physiology may be. And when such leaders as B. Obama and his supporters promote same-sex ‘marriage’ and all-sex toilets and showers and abortion as the level of education and the height (and depth) of American ‘freedom’- it is the sign of the decaying end of a civilization, IMO.
Can the trend be reversed?