Tyler Cowen goes there:
If you take the heterosexual couples who engage in the practice which is sometimes "associated" with male gay marriage, I predict those couples will favor legal gay marriage to an astonishingly high degree. Their marriage is already "affiliated" with that practice, and so the notion of legally married gay men (and the practices which go along with that) does not constitute an extra and unwanted affiliation for their marriage ideal.
My related 2003 article is here.
2006-2011 archives for The Daily Dish, featuring Andrew Sullivan