I think I sit on the fence with this.
I believe a church has the right to refuse gay marriage as legal, it's a fundamental basis of all religion that it's one man/one woman. I don't think gods law, could ever move away from that simplistic view unfortunately and I do believe that a religious person in whatever faith has the right to not think its right but not necessarily wrong iykwim?!
The unity between a man and woman is a perfect one, a woman without a man cannot get pregnant, I suppose this is where the basis of the religious marriage comes.
On the other hand, if you are a person of a certain faith, and god is a very important part of your life I think it would be as important for a homosexual copule to marry in the eyes of god as it would be a heterosexual one, why are they any less important.
I'd call myself agnostic (sit on the fence with most things in my life ha!) I'm not sure what outcome this could ever have. It's not fair to make a religion turn it's back on everything they've taught for hundreds of year for a number of people that could essentially get married in a million other places anyway.