I don't either. But I don't think homosexuality is really behavioral. That is, one is homosexual whether or not one chooses to have sex with members of the same sex. My sexual attraction to my own sex goes back as far as I can remember, which is the age of two. Actual sexual activity began much later, but I didn't get any gayer as I got older. I was gay to begin with.
I don't know, and I don't think anybody knows, the extent to which homosexuality is genetic, but the "behavioral" argument doesn't apply, because sexual orientation isn't behavioral. What you do about it is.
All I can say for sure is that if it isn't genetic, it might as well be, because I was sexually attracted to members of my own sex at an extremely early age, and I would think even earlier. It's just that I can't remember any earlier.