Missed this before, glad I saw it tonight.
When I've ever asked someone who was gay or trans, when did you know?
The answer I've always gotten 90% of the time was "always".
Personally I never thought of it as really a "choice", but a genetic thing, and I've always felt you should just be who you are inside.
This said, my son apparently has a transgendered kid in his grade this year. My son is in 4th grade, he's 10 going on 11, we held him back a year so most of the kids in his grade are actually 9 going on 10. He told me the one kid had dressed as a boy since he entered school, but this year he came to school in girl's clothes and with his hair dyed.
We live in a rural coal mining area, he said the other kids are quote: "totally ruthless mom" in their teasing, and a day doesn't go by without this kid getting teased, mocked, and picked on. If this was my child I think I would rather have him pretend to maybe be something he felt he wasn't until he was older than to watch him go through this hell on a daily basis, because I don't know how someone can cope with that every day and come out of it without some scars, kids can be nastier then adults.
I guess I'm left questioning the parents logic on this one, if it where myself, I guess I would, a. move to an area where there was some hope of acceptance, b. homeschool, or c. pretend until I felt they were old enough to cope better with the crap.
My son thinks he's cool though, he says he/she's a walking dictionary on horror films. My kid's been on a horror/zombie kick for a couple of month's now.