I think that your preference is something you're born with, but usually you don't know what your preference is until you get old enough to realise it anyway. I don't know anyone who thinks they at some point "developed" heterosexuality so it seems silly to me when they say that gay people "developed" homosexuality.
Maybe sometimes people can be "experimental" with their sexuality and enjoy it, but preference is just something you can't help in the end - whether you're heterosexual, homosexual, bisexual, pansexual, asexual...
Sexual feelings of any sort are something that develop in people as they grow older, so I'm inclined to say that homosexuality, heterosexuality, or any other sexual orientation is something you develop... That said, I think which gender you're eventually going to be attracted to is definitely at least partially something you're born with. So, I guess I'm not really sure . (Either way, I hope most of the people voting 'develop' don't think homosexuality is a bad thing or something that can be 'cured'....)
i think it develops in their heads, and im sorry to say that im totally against homosexuality (unless theres a medical problem with hormones n stuff then i guess thats something else). i mean com on, God created us like this: guys r guys n girls r girls. and guys + girls is the only equation here. i dunno why ppl want to change human nature.. i dunno if this is the point of the poll lol but yeah..