What you are saying is that a homosexual gene could no longer exist.
We have, from "Darwin's Ghost" by Steve Jones, that ...
The first members of our own species, Homo sapiens, arose about a hundred thousand years ago as large, thick-skulled, but recognizable human apes.
We also have, today, innumeral living homosexuals, male and female.
Go figure.
Likewise we have homos incessantly raping young boys, an array of pedophiles, beastophiles, and necrophiles, but the narrative promoted by the queers is only their perversion has a genetic basis.