Requiring same-sex couples to marry if they want to keep health insurance benefits they've previously enjoyed with domestic partnerships.

This issue arises in the 6 states (plus D.C.) that allow same-sex marriage.

On the surface, this appears to put the couples on an even footing with heterosexual married couples. After all, this is precisely what they have been fighting for: being treated as a spouse. But some gay and lesbian advocates are arguing that the change may have come too soon: some couples may face complications, since their unions are not recognized by the federal government.

So, when opposite-sex couples decide whether to marry, to the extent that it's an economic calculation, they are weighing a much different set of pros and cons. For example, joint federal income tax returns can save a huge (or cost) amount of money. And under federal tax law, the spouse/"spouse" who receives his/her partner's health benefits has treat the benefit as income and pay tax on it.

If one of the spouses is not a U.S. citizen and is in the country on a temporary visa, the state-level-only marriage "could flag your renewal application and reflect your more permanent decision to stay." Marriage, instead of helping you get to citizenship, would send you in the direction of losing your visa.

What if one spouse is in the military? Getting married violates Don't Ask, Don't Tell, which isn't completely gone yet.

In addition, a state-level-only marriage causes problems if the couple moves to a state that doesn't recognize that marriage (and is entitled, under the Defense of Marriage Act, to decline to recognize the marriage):

Getting a divorce can be complicated, since one member of a couple may have to return to the gay marriage state and live there before their split can be completed.

The employers making the changes [to require marriage to retain benefits] said they spoke regularly with their gay and lesbian employee groups and planned to phase in the requirement. Corning, based in Corning, N.Y., said it would offer a reasonable grace period, though it had not completed the details.

“After waiting so much time for that right, we want them to have the opportunity to enjoy that,” said Christy Pambianchi, a senior vice president for human resources at Corning, which put the policy into effect in New Hampshire and Massachusetts when gay marriage became legal there. She said employees did not raise concerns about the requirement. “They are delighted,” she said.

So the New Hampshire and Massachusetts same-sex couples didn't notice the problem? It took New York. Why was that? Are New Yorkers more legalistic and inclined toward economic analysis? Are they more likely to speak up in their own self-interest even when they are getting something they'd been asking for that's supposed to be good?

Obviously, some same-sex couples are happy to be allowed to get married, but under the law, marriage is a complicated matter. It's not just about pledging your love and devotion. In fact, you can do that without a legal marriage. As Joni Mitchell sang a long time ago: "We don't need no piece of paper. From the city hall. Keeping us tied and true."

Legal marriage is about a whole lot of other things, and the set of things is not the same for opposite sex and same-sex marriage. The decision to get married is a different decision for same-sex couples, and it's not real equality to have to decide between losing your health insurance benefits and entering into the kind of marriage that is works only in at the state level and only in some of the states.