In many sports there is actually no rule that forbid women to joining the other championship. The reason a separate women sport exist is the same as why there

In many sports there is actually no rule that forbid women to joining the other championship. The reason a separate women sport exist is the same as why there are weight brackets in boxing, to allow athletes that score lower in brute-metrics to compete reasonably. Trans women would be less of an issue if women sports did not exist. (Trans men are a different issue if they take hormones, as that often fall under doping technically)