"That will never happen!" they keep yelling about the thing that, you know, keeps happening

[pknopp]

Then I will answer for you. The reason we don't see girls who want to be boys going into the boys' locker rooms and getting naked with them is the same reason why girls are not comfortable having boys who want to be girls in their locker rooms when they are naked. They don't like strange boys looking at them and potentially assaulting them. It's plain and simple, teenaged boys and girls should not be sharing locker rooms, even if some of them want to be the other. We're just putting vulnerable girls at risk by doing so.

This is not a good solution to a problem that doesn't even have to be a problem.

I have seen no examples of boys in girls locker rooms.