What scientific evidence proves that people are BORN straight or g*y?

Question

I tend to believe that people are generally inclined to reproduce (thus they are born with the disposition to be straight) but some choose to be g*y. Yes, being g*y is a matter of behavior, not genetics (in most cases).

Answer 1

Studies are being done, genes that factor in, size of specific brain structures like the hippocampus, and other indications of biological changes have been noted. You have your opinion, I have mine. Personally I didn't choose to deal with a lot more garbage and hardships in life by choosing to be g*y, I just happened to fall in love with a girl.

Answer 2

The answer will likely not be so straight-forward.  Most human behavior, and, likely, g*y behavior, has both dispositional (e.g., genetic) and  environmental (e.g., choosing) antecedents.  Behavioral genetic research tends to find that, at most, we can trace about half of our observations such things back to our genetic sources (bear in mind, though, that this is not the same as finding a gene).  Quite a few things, less.  And it really isn't even this straight-forward.

You might find people with certain patterns of genes, anatomical structures, etc. may have a higher propensity to be/become g*y, but it will unlikely be absolute.  And even apparent anatomical differences may not always be the cause (i.e., did the differences cause one to be "g*y" or did being "g*y" cause the differences?).   It will be a matter of probabilities - and even thinking of someone as g*y...or not, probably doesn't really accurately capture this picture either.

If it was as easy as tracking down a single gene, a single anatomical feature, etc. - we'd know by now.  

To your point that we are inclined to reproduce, so being g*y is maladaptive (therefore, unlikely to be inherited), does presuppose that g*y people don't/can't reproduce.  Maybe this is more of a choice, today, but, historically, marriage, s*x, and family often had little to do with choice, was socially expected or forced - so preference has much less to do with it in the past, as opposed to today.  So, even if there was an apparent g*y set of genes - it would have been pretty easy for them to survive to this point.