Yes, about 114 sources on Wikipedia.

"As of 1999, about 500 species, ranging from primates to gut worms, have been documented engaging in same-sex behaviors.[3][page needed][4] According to the organizers of the 2006 Against Nature? exhibit, it has been observed in 1,500 species.[5]"

So if not DNA, then what else?

https://en.wikipedia.org/wiki/Homosexual_behavior_in_animals

That's missing the point. The question was whether there's any evidence that homosexuality (in humans) is the result of a particular genetic specification. We don't know whether or not that's the case for the worms. All we know is that some worms exhibit homosexual behavior.

It's not missing it. We are in no way different than other mammals in this question. Even the ratios match we observe in nature, so it's very likely that it's a natural process. It can be as deep as epigenetic effect, but I don't see how it's not coded into your system.

We don't even have reliable information on the ratio for humans. Please don't try to tell me that we have reliable numbers on what fraction of worms or chimpanzees are "gay".

There is no source, the gender spectrum is fundamentally based on rejecting science

I think you're confusing biological sex and sexual orientation. The poster above stated that sexual orientation is based off your DNA. There is no gene that determines whether you heterosexual or gay.

It has nothing to do with gender. You're just trying to proliferate your opinion that gender = biological sex. Anyone that is transgender would disagree with your opinion.

Sooooo your source is gamergate/redpill bullshit propaganda. Okay. Have fun with that.