It isn't "3 billion years of evolution" that told us homosexuality is wrong.
Without G-d, objective right and wrong do not, and cannot, exist.
Yes, of course, without God everything becomes subjective. Morality becomes relative. But I’m hesitant to just say “homosexuality is wrong because my religion tells me”, because I’ve basically done that in front of like 20 people, and one replied “Which is why we need to get rid of religion”. I said “You mean get rid of me, right”? He replied “Well, no”, and I said “But you’d have to, because I’m not going to give up my religion willingly”. That gave him pause, but the point is I don’t like letting people think that without religion, problems just go away. But maybe I shouldn’t care what they think.