Why can't we just admit that men are physically more capable at virtually everything, maybe literally everything, athletic? If we did that, then we could call it a one-way street.
If women, or "former" women want to compete with men, have at it, it's like stepping up a league. (Of course they'll lose, but hey...)
And when men want to step down and compete with women, you say no, because they'll obviously (and the data's already coming in) dominate even when taking more estrogen than a soy-drinking-vegan-from-san-francisco.
Once you only apply logic, this really does become simple.