Competitive sports has long been built along discrete gender lines so that women who, admittedly, tend to be smaller and less muscular, could compete against each other rather than big burly hairy sweaty bears (pardon my hyperbole).
Science is telling us that gender is a continuum not a binary thing. The problem is obvious. What to do about those who find themselves in that middle third of the continuum where it's not so easy to tell...or where, for example, a person with a vagina is, in almost every other way, a man. A "woman," in other words, that few more feminine but athletic women could ever hope to compete against.
There are several solutions, none of them making everyone happy. You could simply forbid that middle third from competing at all. You could have a separate gender bender category. You could introduce a handicappiing system. See, all of those options will be offensive to someone.
There is, of course, one other solution: simply don't have gender categories at all, but I don't see that pleasing everyone, either.
And then there's the other problem first rearing its head in the 2012 Olympics with the first appearance of someone competing with prosthetics. Oscar Pistorius, a South African runner, competed with artificial feet made of carbonfiber. He runs very well. Well enough, due to his times, to compete in the Olympics. The problem isn't his times, it's how to compare his prostheses to natural feet. So far, it seems impossible to figure out what to do. They are allowed for now, but what if someday only people with prosthetic feet can hope to win?
What's the solution? A handicapping system? There seems no way to know how to set one up fairly. At least when everyone has natural feet, there's an air of fairness about it. When a person with artificial feet is competing, and competing well, it may be asterisk time, or time to send them back to the Special Olympics or, if not that, an Olympics just for people with prosthetic limbs who are getting times competitive with people with natural feet..
Things used to be so simple.
I think that all sports teams should be complete gender mixed. The women will just have to bulk up to the same level as the men, its totally possible to do that. Sports is still too male dominated.
Or, how about two categories: women's and open to anyone?