There's no "gay" gene. The one study that suggested such was found to have too many exceptions to be worth the paper it was written on.
Originally Posted by I B Hankering
Nobody says there's a gay gene any more, indeed it's not that simple.
From your source, "Homosexuality may be triggered by environmental factors during childhood ... The finding is highly controversial because it suggests that some men are not born gay, but are turned homosexual by their surroundings...."
Is it possible that environmental factors after birth and during childhood would not only cause a boy to be more likely to become homosexual, but also cause him to have a small INAH3 region in the hypothalamus? Possible I guess, but unlikely:
https://science.sciencemag.org/content/253/5023/1034
In other words, there are biological differences between gay and straight men.