Peter, in a couple of comments below, has asked why "same-sex marriage" is my preference over "gay marriage" and astutely pointed out some problems with the NLGJA's wording. Prints the Chaff has weighed in too.
I admit, the difference between same-sex and gay marriage is small. I mean, everyone calls it gay marriage, right? I am bothered by several points though, which I list here.
1.) The basic problem of accuracy. I wrote about this earlier. Gay people can already get married, just not to people of the their own gender. This might seem pedantic, given that you can deconstruct "gay marriage" to mean "marriage for gay couples," or something like that. But the more I think about this point, the more I believe it's valid.
2.) "Gay" only stands for one side of the equation. The mainstream media doesn't always make this distinction, but in the LBGT community (that's lesbian, bisexual, gay and transgendered) gay refers almost exclusively to men. Given that lesbian couples are part of this controversy too, "gay marriage" strikes me as narrow.
3.) The legal questions of this debate do not specifically deal with sexual orientation. They exclusively focus on gender. That's why the constitutional amendment floating around the U.S. Congress right now doesn't use the words "gay" or "lesbian." It would block any marriage between persons of the same gender, regardless of their sexual orientation.
4.) Neutrality. "Same-sex marriage," while colorless, describes the issue in a simple and broad way.
All of this said, I don't necessarily think "gay marriage" should be banned from newspaper pages. It comes in handy at times, and we don't want to put ourselves in the position of eliminating easy-to-understand options.
"Same-sex marriage," as I said, remains my default for now.