Posted: 05/10/2014 at 18:26
There's also a variety of genetic syndromes that occur where as well as the basic XX (female) and XY (male) combinations, there are things like XO, XXY and XYY going on. I don't know enough about genetics to know precisely what effects this will have, but I imagine there could be some unusual hormone levels in there.
I also wonder what you do if someone transitions from male to female. I vaguely recall a tennis match between Billy-Jean King and someone who'd done this.
More questions than answers from me!