I never made a choice.
I knew I preferred males from about 8 -- my earliest memories with any sexual content were with other bois and I never had any thought of sexual contact with a female -- although I knew how straight sex worked, it always meant nothing to me, and still does.
So, from an anecdotal perspective, its pretty clear that I was born gay.
And what you are using yourself is anecdotes, so I presume that anecdotes are acceptable as proof within the discussion construct that you have created..
Beyond that of course, the most compelling things are the fruit fly study, the various studies of identical twins and the genetics assay performed by Dr. Camperio-Ciani and colleagues -- which showed one of the methods via which homosexuality becomes both genetically viable and evolutionarily preferred.
We may even be near to determining the penetrance of the gene or genes responsible for homosexuality (about 50% give or take would be my guess as to what the eventual number will be determined to be).
As for "turning gay" which is the implication of your discussion of the 50 year old man. Not possible. Now there are a couple of things that do happen. I had a 38 year old friend recently come out -- I never dreamed he might be gay -- he was married at one point. I always assumed he was straight. The fact was, as he admitted after coming out -- that he always knew, but he also knew his mother would reject him entirely (she did) and he was afraid. So, he had sex with a woman for whom he felt nothing, and spent the first 25 years of his sexual beingness pretending to be straight, and thinking about guys to be able to perform with women. Sad? Yes. Uncommon? No. I've known others. So that is a possibility for the 50 year old.
The other possibility is that the 50 year old was a bisexual, who kept his feelings for males "in check" for many years (after-all, even if there are not significant stops, as my friend had, within the family, society prefers people to be heterosexual, and it is easier for a bisexual than a homosexual to appear to fulfill its strictures.), but who always had stray thoughts about how hot/sexy/attractive guys were -- and who finally, for whatever reason, had a sex act with another male. In that case, quite often, the man goes through a crazed all male stage. That doesn't change the fact that he was bisexual while having sex with women, and is bisexual now, while having sex with men. Given enough time and good health, his interest in women will also reassert itself.
To finish, the straw-men you set up are not compelling. Obviously the idea of a man born to direct movies is facetious, but if you mean some men are born more naturally creative than others -- then I challenge you to find 50 women who have had more than 3 boys and assert to them that all their sons are equally creative. You will learn that in fact, some are more creative from a very young age -- so there is a recognizable genetic predisposition toward creative, which may lead to directing movies in some cases. As for alcoholism, very few serious geneticists would agree that there is no genetic component. In fact, genetic penetrance comes into play again on this topic. For some people with a predisposition toward alcoholism it takes years of drinking to kick in, while for others, the single glass of wine starts them on a life of fighting alcohol...
In short, your assertion is, while interesting, unsupported by anything other than anecdotal evidence -- and the anecdotal evidence is either weak and easily refuted, or false - as is the case with your various straw-men constructs. Anecdotes from other persons and the solid research going on in the field all strongly indicate that in fact, homosexuality is inborn.
Kind regards,
Reynolds Jones
http://www.rebuff.org
believeinyou24@yahoo.com