I have been raised to not be gay, my step dad is homophobic, badly. My mom ignores it but calls it a choice. Yet, somehow all the signs are there for everyone, its kinda "obvious" Of the few people i told, most of them could tell.and my step brother used to torture me about being "gay" with my straight best girl friend, who I have actually never been attracted to. I dont know what to think of myself anymore. Honestly
My family is West Virginian, its not a very tolerant place (not that I don't love the place, go mountaineers) but I get where you're coming from. I havn't outed to anybody but I think my sisters know and my brother definitely knows even though I denied it when I was younger. This comment wasn't very helpful, just wanted to let you know that you're not alone. (+2 points for the Doctor Who sig )
I'm no expert, but I've been there myself (grew up with homophobic family and some homophobic classmates) My guess is you are what you feel, and think of yourself like that, and to hell with what other people tell you that you should be. As far as it being a "choice", doing something or pretending to be something that you're not is of course a choice. How you feel inside however isn't a "choice" any more than if you're mom or step dad tried to choose to be someone of the same sex.