The high court of New Jersey ruled today that same-sex couples must be treated equally under the law as married hets, although it's up to the state legislature whether to call such arrangements marriages, civil unions, or, perhaps, mulligatawny. I mean, it's just a word, right? If the underlying rights are equal I'm willing to cede "marriage" to the straights on their fifth husbands--all in the interest of preserving the sanctity of the institution, of course--and accept whatever term legislatures want to attach to our unions.
In my perfect world, everyone who officially couples up would get a civil union. Then if you wish to have your civil contract solemnized in the religious tradition of your choice, you're free to do so and appropriate the word "married" as your own.
Thinking about the Christian right's arguments against gay marriage, their protestations about the eternal sanctity of marriage as one man, one woman, world without end, I don't see that my suggestion would be that objectionable. If they truly see marriage as a God-ordained institution intended to both carry out God's plan for humanity AND reflect Jesus' relationship to the church, they should be happy to get all the heathen and atheistic riffraff swept out the door.
I have some good friends who have been happily married for nearly ten years, the original marriage for both of them. They are also atheists and have no intention of reproducing; in fact, the guy got a vasectomy in his 20s because he knew he never wanted kids. They're involved with their nieces and nephews and have a couple of dogs, but their marriage neither perpetuates the species nor glorifies God in any manifestation. So the only criterion of Marriage they fulfill is having different genders. A long-term lesbian couple I know, in contrast, attend church regularly, sing in the choir, and raised their daughter in their faith. They are a much closer match to the model of Marriage put forth by the fundies except, of course, for the niggling little detail of sharing four X chromosomes between them. Yet another couple I know is stridently evangelical Christian and conservative... and between them they've racked up a jaw-dropping nine marriages, demonstrating either boundless optimism or being hopelessly jaded.
Which one of those is the real marriage by fundamentalist Christian standards? Any of them? Which comes closest to that model of perfection they hold up, that precious institution that is so fragile as to likely implode if two guys exchange rings? Letting gay couples in the door for civil unions with everyone else, while letting individual religious congregations decide what they're going to bless as a marriage (infertile couples? second or third marriages? biracial couples? mixed faith marriages? pagans?) should satisfy the logical needs of most of us while simultaneously massaging the egos of those who need to feel exclusionary. Let them be True Scotsmen and define "marriage" however they want, so long as the legal rights and responsibilities are conferred on everyone.