I think you missed the point. Receiving a squirt of testosterone in your brain during gestation is what tells you you are a male, not a gene. If you do not get this squirt of testosterone in your brain during gestation, you brain develops into a female brain.
Now, while this might clearly explain why some children want to have sex change operations, because they do not think they are of the correct gender, by itself it does not explain why individuals with incorrect brain gender assignment would be homosexuals.
Except in the case of animals that are mammals, they are. All of them. All of the time. Animals act based on their brain gender assignment. What their genitals are means nothing compared to what their brains are.
So why should humans be different? To say so, you have to extrapolate an even stranger psychology, what amounts to "male lesbians"; which would be a gender male, but with a female brain, which is itself homosexual, which is why he is attracted to females. This is crapola.
But back to genes. While a gene does not by itself determines sexual brain assignment, it *can*, most definitely, be the switch as to whether that squirt of testosterone is *correctly* given to males, and not to females.
And the resulting squirt of testosterone is all important.
I used to think it wasn't as complicated as it is, but
same-sex attraction is really quite complicated. No one gene is going to cause same-sex attraction. The experts have been saying for years that environment is the major factor. Other minor factors or traits might be considered gifts, if I may.