“However, and a big however, while this is enough to determine animal sexuality, it is *not* enough to determine human sexuality.”
How do we know?
Little children who play gender-different (their interests, etc) may grow up to be straight, but a significNt amount of these little kids ( the sporty girl with the desire to wear boys clothes and short hair, the boy who loves pink and nail polish) DO find themselves attracted to their own sex at puberty.
Please cite sources of studies, otherwise your statment is less than meaningless.
Believe me, this was a top concern, again all the way back to the 1960s.
Farmers regularly use plant estrogen to give them better yields of their crops. But plant estrogen is very similar to human estrogen, and also acts as a testosterone blocker. Likewise there are other, industrial synthetic chemicals that also block testosterone. They were scared that there was soon to be a huge epidemic of feminized, homosexual males.
But it didn’t happen. While there has been some increase in the number of more androgynous males, the rates of homosexuality are about unchanged.
Relatively vast amounts of hormone supplements are dumped into our sewers, enough to clearly affect some populations of freshwater fish, but somehow we have either evaded it or our bodies are able to overcome it.
The biggest human effect seems to be in an increased number of children who need gender reassignment. Even Saudi Arabia recognizes such situations and permits reassignment.
So, for example, a boy “knows” he is a girl in a boy’s body. But even after reassignment surgery, he, now a she, is still sexually attracted to girls. This ends up with the unenviable situation of homosexuality that really isn’t.
I believe most studies of homosexuality is carried out by homosexuals, since they are the only ones interested in why, so their research should be considered suspect.