Personally, I am against it. My biology teacher once told me, "God put you on this Earth to reproduce." How can you reproduce with two men or two women? I just don't think it's right.
Not that I am strongly against it I think the bible teaches that like wakeboarder said you God put you on this Earth to reproduce. Although that isn't strictly true but it's the modern age that has introduced gay marriage it's not something which has been taught which is why it's not looked upon fondly.
I am a religious person, or so I think myself to be (Roman Catholic) and though the catholic church is against the right to gay marriage, I say they should be able to do whatever the fuck they please. I don't really think being gay is a choice, but I'm not quite sure. In the animal kingdom, humans are not the only homosexual animals. Mammals of all kinds are homosexual, and yet they aren't shunned from their prides/clans/whatevertheymaybewithin, unlike today's society, where if you try to come out of the closet any time before college, you're instantly pushed away, as if every single human of the same sex is just your sex toy. I'm quite sure that I don't want to have intercourse with every single woman I see, so if I see a gay person my age, I think the same thing- chances are they don't want to have sex with me, which is fine because I'm straight. Even though Christians are taught that gay marriage (Or just BEING gay) is wrong, I was taught that it's still socially acceptable to be gay, and being homosexual can be part of original sin. I didn't grow up in a gay loving or super modern catholic house. In fact my parents call gay people 'faggots' quite casually, and my sister likes to go up to Portland, where she now lives, and they call it 'Dykeville' It just gets me heated when my parents act like that, I think everyone is created equally. Thinking otherwise is just fucking ignorant.
I'm religious in the sence I believe in God, but I don't follow many of his teachings, nor do I take the bible at its word about how I should lead my life. That being said I still hate homosexuals for the sole reason they disgust me, and thus I am against allowing them to marry. Hating them to me is the same as hating a spider is to people, I didn't choose to any more than they chose to be gay, and I could probably change my views if I opened up and exposed myself to more gay people, but I feel no reason to so for the forseable future I oppose gay rights.