Actually yes. He mentions having a crush on a girl as a kid, makes a remark on how cute Liara is, hints at his enjoyment of the strip club, and that's all in ME1. Pretty sure there's more evidence of heterosexuality, but it would only lead back to the point ofveloper said:The devs are prolly going to bring him back from the dead too regardless of what you did in ME1.
Making him bi or gay then is a relatively minor point. Did Kaiden even show any indication of being straight or anything at all, if you played only the male protagonist?
1) Anybody can choose to be gay and straight despite having a history of the other
_This, when it comes to humans at least, it correct
2) Kaiden's ME2 speech
_I won't make fun of Kaiden, and I'm not saying he should or shouldn't be gay. All I'm saying is that his speech to Male Shepard on Horizon felt...well...it felt more emotional than anything Ashley had to say, put it that way.
So yeah, Kaiden is hetero, but I guess there are ways he can be gay for 3 without it seeming totally out of left field. However the topic of the thread, the fact that homosexuality was never in ME until now and how they'll try to pull this off, is a much different matter than making a mostly straight character gay.