I'm for it. Its a human right issue, we live in a free society where every citizen should have the same right as others, where there is a seperation between church and state and where people can choose if they want to get married or not. Some people have the argument of "Well they can have civil union why don't they just take that?", straight couples can also have a civil union, why don't they just do that?
Not allowing gay marriage sets civil rights back 70 years. In the 60s a judge said that God didn't want interracial couples getting married because "God put coloured people on different continent so they wouldn't mix.", the arguments against interracial marriage back then are almost the same as gay marriage today.
Best way to fix the problem is allow it, but also allow religious establishments choose if they would provide the services for gays.