Bill Nye (he of The Science Guy fame) answered a question from an online user submitted to Big Think about the relationship between evolution and homosexuality. The user wondered, does homosexuality make evolutionary sense if species are driven to promulgate?

“If the purpose of a species is to reproduce and survive, how would it make sense evolutionarily for humans to have same-sex preferences? Are humans the only ones who practice homosexuality? And if so does this mean that homosexuality is a product of human's personal whim as opposed to instinct?”

Nye responded,

“…[I]t's a spectrum. I don't know about you, but I have known a great many gay men who are married, who have babies, who have kids. So apparently — I'm not an authority on this. I'm an observer of the human condition. Apparently there's a spectrum. Some people are more inclined to have sex with people of their same sex than others. And I think if you just watch the news right now, you can see that for yourself. And so being somewhere on the spectrum of heterosexual with homosexual being on that it's not genetically lethal; you still have kids anyway. And you'll hear people talk about the feminine side. You'll hear people talk about the masculine side. You'll hear women use the expression, “Well she's got a lot of balls which can't literally be true, if we're using balls in that conventional construction.” So I would say that it's something that happens in nature.”

Nye also pointed out previous research that found evidence of homosexuality in species beyond humans including chimpanzees and Bonobo's.

Rather than worry about homosexuality's role in evolution, Nye suggested, “Let's celebrate being alive everybody. Apparently it's just something that happens in nature and look, we're all here.”