It’s a very difficult one for me. On the one hand, it probably wouldn’t be fair to have them forced to continue in a male sport. Equally, it does increase the probability of a physical advantage (obviously though it would be ridiculous to assert that anyone who went through “male puberty”, for lack of a better term, is automatically physically superior). And even further, it would probably be exceedingly difficult to create a third (and possibly more) sport division strictly for those who fall outside the, er, “traditional” gender binary.
Not trans nor a woman, though, so ultimately not equipped to make that call. Trump certainly has no business doing so, either.