I love a quote I found online..
"The fact that you can no longer sell your daughter for two goats and a cow means we have already redefined 'traditional' marriage."
Marriage is not an exclusively religious rite, and considering the whole "separation of church and state" idea, religion should have absolutely no say in the legality of it. As an atheist, I would be pretty upset if someone had tried to stop ME from getting married...
Other than that, the main reasons I have seen against it...
1) if we give them that, next they will be wanting to marry animals.
...because you know, a dog has legal standing and can sign a marriage certificate.
2) what will stop them from marrying children?
...ummmmm... Child welfare, maybe? The same thing that stops an adult man from marrying a little girl...
3) it's just plain "wrong"
....well, it wasn't too long ago that interracial marriages were just plain wrong... How silly does that seem now?
4) they will adopt and raise gay children.
....I would MUCH rather see a child raised by a gay living couple, than suffer through our country's system. If they turn out gay, so what? Also, if things worked that way, there would be no gay people at all, considering most of them were raised by straight parents... Wouldn't you think if gay people raise gay kids, straight people would raise straight kids...?
Anyone who is so against it needs to get their noses out of other people's business. If they get married, all it means is that they will have the same LEGAL rights as a consenting straight couple. It's not going to change anything other than that.
I find it very sad that they are denied these rights. I had a close friend whose partner of 25 years was killed by a drunk driver. They thought they had made all the documents necessary to have essentially the same rights as a married couple, but apparently they forgot something, as his partner's parents (who had kicked him out of their home when he 'came out' to them at the age of 16, and would have nothing to do with him...) took the body and had it shipped home, where they cremated it and dumped the ashes. Because they weren't legally married, my friend couldn't fight to keep it, and wasn't even allowed to attend the funeral. He was completely devastated.
ETA: to those claiming that they should be given a civil union instead of a marriage... Y'all do realize that marriage predates Christianity, right? Just because it is mentioned in the Bible does NOT give you exclusive rights to the word.
I am MARRIED to my husband, not participating in a civil union with him. There was absolutely no religion involved in our MARRIAGE. We are no less married than the Christian couple next door. We have no more right to be married than the gay couple down the street who wishes they could be. Just because your religion doesn't recognize it, doesn't mean you have the right to say it isn't real, or dictate who it applies to.
Also... You can KEEP your Christian marriage... You know, the one that says that a woman has to marry her rapist, that women are the property of their parents until they are sold to their husbands, that women must be subservient to their husbands, that marriage is not valid unless the woman is a virgin, that a widow must marry her husband's brother... Yeah... Enjoy. Or are you only going to pick and choose which parts of the bible apply?