LOL A baby cant be gay...ok jokes aside....To my knowledge no they arent born that way, as time goes on they might develope a certain urge for the same sex...which i actually find disturbing but i dont act on it or anything so w/e to the last part i said
So, according to your logic, people are not born geniuses, they become geniuses later in life, since one baby is not smarter than another?
Just because something shows up after puberty doesn't mean you weren't born with it.