Let’s just cut the Gordian knot and get rid of marriage:
Give gay and straight couples alike the same license — a certificate confirming them as a family, and call it a “civil union” — anything, really, other than “marriage.” For those for whom the word marriage is important, the next stop after the courthouse could be the church, where they could bless their union with all the religious ceremony they could want. The Church itself would lose nothing of its role in sanctioning the kinds of unions that it finds in keeping with its tenets. And for non-believers or those for whom the word marriage is less important, the civil union license issued by the state would be all they needed to unlock the benefits reserved in most states, and in federal law, for “married” couples.
H/T: Andrew Sullivan