well then in that case it's practicly a choice.
this seems like a genetic thing, given how I do beleive there is documented diferences in the structure of the brain (though this could just as equaly likely be from harmonal stuff during pregnancy) and things of that nature. however I doubt the distinctions are as black and white as Kaz was makeing it sound.
as for getting selected out, that might have gotten a help ironicly from the prudey customs of many cultures, were homosexuals that would have otherwise taken a same sex mate were forced to act against there nature and mate with someone of the opposet sex, though it seems like humans have an exadurated level that even that wouldn't completely acount for, not supriseing seeing as the second most closely related animal (the bonobo) is the most "hell yeah I swing that way!" one on the planet. but evolution sometimes works in less than streightforward way, perhapes haveing a homosexual in your family does, or at one time did, provide some sort of evolutionary advantage.
however if homosexuality is in fact a disadvantage as it does on the surface at least apear to be, then the best way to get rid of the problem would in fact to do nothing about it, let people live life the way they want to live, if they have some sort of tendancy twards a disadvantagus lifestyle then they will become extinct in a few generations.
but whatever the case may be it has about as much baring on weather a person is 'good' or 'bad' as does being right or left handed.