Is there any proof or evidence that homosexuality is morally wrong?

[Lady Catherine]

A lot of people make this claim, but I rarely hear anyone supply any proof or evidence to support this claim. What is the proof and evidence that homosexuality is morally wrong? And if there's no proof and evidence, why do people make this claim?
@Tyvern: I know, but there's a lot of people who assert it as a fact.
@Paul: I know that story, but I asked for proof and evidence, not quotes from a story. Do you have any proof or evidence that it's morally wrong?
@Nick Sady: Do you have any proof or evidence that it's against nature's law, or that it's unnatural perversion?