Whoa, do we know that Greece didn't have a 3.5% rate of homosexual sex? Just because a man took a boy under his wing in Ancient Greece does not mean he necessarily had sex with him often, if ever.

You then claim that sexuality is not determined by biology. My opinion is that it is. Because nothing else explains my personal preference. I'm 60. When I was young I was hit upon by two homosexual men, who I like as people, but I had no interest in their sexual advances (which I barely comprehended at the time) though I thought about sex with girls every proverbial 15 seconds. That is, no one told me homosexual sex was wrong. One of the men my parents introduced me to (to do some work about his business--they didn't believe he would try to "molest" me).

I'm just one data point. So not claiming sexuality is 100% biological, only that I would not give any "short answer" that is one way or the other.

You write an interesting article. But your youthful enthusiasm shows. Current cultural attitudes have clouded your anthropological assessment. You could do with an older woman or man to guide you ;)