We have a crumpled little piece of parchment, which means less and less these days, which grants equal rights to all and this document stands above all others when it comes to these matters.
Equal rights is to support civil unions not re-define what Marriage is

God gave mankind ( and woman kind ) something called "Free Will". If people use that free will in a way that goes against your beliefs, tough shit, it is between them and God. ( or maybe you are God, Hmmm? )
You need to read a little further especially the part about when God sends Lott to Sodom