Speaking as a scientist, I can tell you that we don’t deal with questions of “sin,” “absolution,” “lifestyle,” or even “preferences.”
Nonetheless, I would find it absolutely fascinating to discover to what factors are involved in determining the strength, direction, and persistence of a person’s sexual orientation. No doubt, some factors are genetically or hormonally programmed (i.e., inborn). Others probably depend on the “luck of the draw” in terms of how much the person enjoys what happens to him or her in his first few experiences—or the stimuli that give rise to his first sexual fantasies—and to classical and operant conditioning which follow when these fantasies are used in masturbatory fantasy. In our culture, boys are expected to masturbate from the age of about 10 years old until they can obtain legal sexual partners around the age of 18 years old.
In other words, on top of everything else, male sexuality is subject to at least 3 to 9 years classical and operant conditioning, which every sick and twisted masturbatory fantasies the Internet has to offer has been habituated and ingrained into his “turn-ons,” kinks and fascinations. All this, of course, is modified by various forms of peer pressure, commercial manipulation, exploitation, and the social marketing of buy our stuff an get your anorexic (almost boyish) dream girl. And there is also a declining notion that homosexuality an homosexuality are mutually exclusive (which was introduced in our culture around the 1870s).
Look at the HBO Series “Rome” or the Starz series “Spartacus” Blood and Sand” for contrast between those societies and ours.
What I see from my admittedly limited point of view is that when people say “I don’t care about when others say they are “gay” or “straight” what they are really saying is that these distinctions are becoming increasingly irrelevant in modern times. There are plenty of straight men who, under certain conditions, will have sex with men. You might even be able to get them to admit to being “technically bi” in order to humor you.
In species where there is homosexuality, it is not because that there are “straight” and “gay” individuals or couples. About 20% of the population mixes it up—not because they are programmed at some sub-volitional level, but because there is something like volitional choice going on at the aesthetic level.
http://www.timesonline.co.uk/tol/life_and_style/article1288633.ece?token=null&offset=0&page=1