I've got an easier solution to the whole bathroom thing though.
Instead of calling it the men's/boy's bathroom or the Lady/Girl's bathroom. Just label it the Penis bathroom and the Vagina bathroom.
Problem solved. Transgender kids don't have to be labeled a sex they are uncomfortable with. Parents don't have to worry about the wrong sexual organ being present in the bathroom of their children.
Speaking of the whole transgender thing. Is it wrong that when I'm in the line at the airport that I refuse the x-ray screen then claim to be transgender to get a free rub down by a female or just gross? I can't decide and start to feel guilty about it but then my balls get rubbed and everything is just ok.