I know they do twin studies. My point was that I don’t know if such studies are completely fool-proof.
They do seem to indicate that nature plays a big role.I have seen things about how they often marry people with the same name or give their kids the same name. Which is rather interesting.
However, I am skeptical of studies. There may be a lot of bias involved. For example, maybe the people performing this study wanted to prove that being gay is genetic, so they found a way to do the study in such a way that it would “prove” what they wanted it to prove.
I do agree though that nature and nurture and bechira all play a major role.