On the radio this morning, I heard various groups who were speaking out against proposed changes in government employee insurance coverage which would recognize civil unions. Two religious "leaders" pointed out how they could attest to the "spiritual, emotional and frequently physical harm" that often comes out of non-married cohabitation. They used this as "proof" that same-sex couples shouldn't be allowed to marry.

If you think this sounds like circular reasoning, you are correct. It was actually more blatant in the original than what I recalled here.