Well, I doubt many lesbians are born that way. I've heard some stories about 12th grade girls in a certain high school that strongly indicate to me that lesbianism can easily spread in a wave. It probably is the case that some boys are so strongly effeminate at such a young age that it is going to be difficult for them to identify as heterosexual. So you are right there. But this is not at all true with tomboys.
It probably is for the best that homosexuals, if they are not going to be celibate, get married in a Metropolitan Community Church or some such, whatever people might think of the theology in those places. They can do that today as in the 1970's. However, as shown in Stanley Kurtz's articles on the death of marriage in Scandanavia, once gay marriage is well-established in law, marriage gradually loses its allure for men of WHATEVER orientation. Now gay marriage is this exciting new thing and so has some attraction for gays, but once it is tamed by being the subject of pictures in first grade reading textbooks, it will lose all attraction for gays, and not sound too thrilling to anybody else.
The situation is serious because I don't think the marriage amendment as currently worded can pass. I hope the President tries to water it down to something easier to get through the state legislatures -- probably just allow for pure state-by-state marraige laws not honored reciprocally. Then we'll see which kind of states are best for children to grow up in.
There are some women's colleges where the girls are described as LUGS; Lesbians until graduation.
Sounds like they're making a choice.