@ErinInTheMorn The hard part of this question is that testosterone improves performance in certain physical tasks related to sports, and people with testes tend to have a lot more of it. Anyone can get performance benefits by taking more testosterone, which is of course rightly banned. So I think it is clear that some kind of separation in sports is helpful, but the hard part is drawing the line. I thought this #Radiolab covered it quite well: https://radiolab.org/episodes/dutee