It’s sad you would get downvoted for providing evidence that goes against conventional wisdom, just because it’s now considered socially taboo and stigmatized to say anything other than “sexuality is always determined at birth”. The reality is: most of the times sexuality is determined at birth, but there isn’t sufficient evidence that it’s the case 100% of the time. If anyone takes the time to read the actual GWAS papers on homosexuality, they would realize the genetics are far more complex than the conventional wisdom.

Also, on the one hand, scientists have discovered single genes that, when mutated, increase same-sex mating behaviors in animal models. On the other hand, there’s little evidence that such single genes are responsible for sexual preference in all humans. In all likelihood it is a combination of both multi-genic (and epigenetic) and environmental factors. Which means that blanket statements most likely aren’t true.