I am not completely resolved about how XY females like Caster compete.
But, my issue with males in women's sports is about them pushing out women from competition until we are left with two categories for sport: Mens (elite males) and Women's (mediocre males).
The natural rarity of XY females is that even if they are included and win, we will never be in a situation where we have two categories for sport: Men & XY females.
I really am torn about Caster. She has known herself as female all her life, found that she had and extraordinary talent but didn't know why, dedicated herself to developing that talent without the benefit of male privilege.
I am certain that it is unethical to ask her to take harmful drugs into her healthy body in order to be able to compete.
So the intersex question is still not resolved - yet it is a side issue and not one that has the power to ruin sport for women.
However born XY males should never be in women's sports. Ever. No matter what they identify as or what they do to their bodies. This is the focus and there should be a blanket ban now. NOW! Not tomorrow (- in fact, even yesterday - we should be reviewing all trans wins and giving the titles to the women who were robbed).
The nuances of the fairness of people with intersex conditions competing require more thought to really thrash it out and it is best to take all the time the decision needs, instead of being hasty.
But these are not relevant to the trans issue.
No XY men in women's sport NOW!