Someone asked on a mailing list I subscribe to whether sexual attraction followed a 2-dimensional model. Ugh, so so wrong! No, that isn't even close to anything real. This is the complete form of the equation for sexual attraction:
Fetishes if any + face (neurological averaging) + abstractions (core values) + body-part attraction (tits, ass, legs, arms, genitals) + overall body proportions + interaction dynamics (dominance, submission, attunement, etc) + assortative mating (non-core values).
And I'm leaving out pheromonal attraction because I don't know anything about it.
Now gender identity by comparison is MUCH simpler! It's just core values + non-core values!
Of course, what people are actually interested in is the dimensional decomposition of the solutions to these equations. Well, I will simple them up for you to understand: that whole male vs female attraction shite is oversimplified crap spoonfed to simple-minded idiots.
See, the way it works is that sexual arousal is semantically content-free. It has no meaning! You're not attracted to ANYTHING, at all. Except maybe "people". Or if you have fetishes then the fetish in question. Otherwise, it's just things that turn you off. Or things you're conceptually attracted to. Oh and beauty but beauty is just neurological averaging and is essentially non-sexual.
And things like core values and non-core values? They are *too complicated for idiots to understand*!
Finally, to answer whether sexual attraction is a choice, when the sexual attraction equation returns negative numbers for the entirety of one gender, then that person is exclusively attracted to the other gender. When it returns negatives for both genders then they're asexual. And when it returns some positives in both? Well in that case, take a good look at the above equation and realize how fucking retarded your question is.