Well here's the problem. You have different rights with your partner and such if you are married. However marriage is related to/based on the Christian religion.
Separation of church and state. I don't give a fuck what the bible says or how someone interprets it. If marriage has any legal significance outside of it being a Christian "ritual" as I shall call it, then you can't put some christian morality upon it.
I really need to read the anti-gay stuff in the bible...because I somehow doubt that God's word is telling you to hate eachother...
