One argument that has gotten me is.. how many HETEROSEXUAL couples fail? Far too many. At least half here in the states. What right do they have then to tell gay people they can't commit themselves to one another legally? I'm a Christian, and I see both sides of the argument, but its getting ridiculous. Straight people are no better than gay people. At this point I think that civil unions are a good compromise. Then those gay people who are committed to one another have all the same legal rights and responsibilities as their straight counterparts.
Let God be the judge.
And one thing, isn't it far more responsible on the whole to encourage commitment and fidelity? It's safer.