Here is a thoughtful, calm and well-reasoned argument for why gay marriage is a bad idea. Aaron Fruh nails it when he says:
The argument for same-sex marriage is that a state that denies rights to romantic unions is discriminatory and unjust. It seems that supporting gay marriage has become a litmus test for whether a person is open-minded and politically correct. Gay marriage? Check no, and you're a homophobic, morally insane bigot. Check yes, and you've evolved and blossomed into a well-balanced and thoughtful genius who has enough good sense to know what's best for an open society. A seeming rite of passage, supporting gay marriage is the Nirvana of a free, nondiscriminatory republic. Some (erroneously, I think) try to compare the gay struggle for equal marriage rights to Rosa Parks and the civil rights movement.
(The link to the full article is here.)
When you posit something that changes so much you should be able to adequately explain why. So far, the reasons for gay marriage are about as deep as saying that "it's about time."
For more of my thoughts on same-sex marriage, see my Chicago Tribune column on Tuesday, May 15.