Gay relationships have existed since before humanity as we know it did.
there's more gay people than redheads

Do you have sources for these? I mean, if you show them to me I'll believe them but they seem kind of dubious based off what I already know.

Just because it didn't make any babies doesn't mean they weren't around.

Yeah, no, I'm not arguing that. I'm just saying, if the majority of humans share this trait, and the opposite can't be "passed down" in the genetic sense, that's what makes it "normal" to people. So yes, I am saying it's about numbers. If it's true what you say about redheads, though, I think that's because it's just a more visually appealing trait despite how rare it is. But that's neither here nor there.