Who says the traits have to be displayed? If you're a kid and taught something is wrong then you'll avoid it in order to avoid punishment. Also perhaps it isn't as noticeable at a young age and as the child matures emotionally it becomes more and more apparent with time that they are attracted to members of the same sex.

I can tell you I've never made a "choice" to be straight. It's just how I've always been. Could it then not be the same for homosexuals? Does it really make much sense to expect someone's sexual preference to be simply "Hmm, I want to like boys" or "I want to like girls." It doesn't seem so simple to me, but that's just me. I'm sure the environment the child grows up in would have some sort of effect on it (but that doesn't make it the child's choice by any means) ...like if a boy is molested by a man they may be more likely to be homosexual ...but I really doubt every gay male was molested as a child so there has to be something else.