[ristlane]

Not sure why you're being downvoted. You're right that human sexuality is nowhere near as clear cut as blonde/brown hair, or spotted fur on animals.

Still, that doesn't mean genetics do not play a role in determining human sexuality, binary or otherwise.

[klmadfejno]

Likely because it's just an incorrect statement, and vaguely accusatory. If you have a dataset of people that asks them if they identify as straight or gay, with no alternative, you're going to miss a lot of nuance, but you'll still likely have a useful dataset for extracting genetic effects. Most people would not describe their sexual orientation as fluid at all. You absolutely can crop off valleys and call it good science.