Marriage by definition is between a man and a woman. What gay people want to do is a civil union, not a marriage. So I am against gay marriage but I don't care if they want to do civil unions. You can't redefine stuff thats been the same for centuries because people want to get mad and change the rules.
I don't even know why this is up for discussion anyone can marry whoever or whatever they want. I mean... there was a guy who married himself, a woman who married a snake, and a man who married a goat plus the list carries on.