Questions with a flawed premise that (usually) comes from transphobia are not taken well. If you want to know if it's an issue, I suggest you actually ask women in sports rather than speculating that surely we must segregate trans people.

But to give a hint to the answer: black women can compete in sports in the US now, but not too long ago there were questions of biological fairness. If you asked those same fairness questions today, people would justifiably assume you're a racist asking leading questions. Something to think about.