This morning on CNN, they asked viewers to email their opinions to the question: "Should there be a Constitutional amendment banning gay marriage?" One of the replies said, "People who want to ban gay marriage say it's to protect families and children. I would believe them if there was a ban on rapists, child molesters and wife beaters getting married."
Excellent point.
On a side note, marriage is not a right. It's a privilege. That's why a license is required.