A good companion piece is the column by editorial page editor for The Atlanta Journal-Constitution, Cynthia Tucker.
Prohibiting same-sex unions would have absolutely no effect on the state of traditional marriage. Britney Spears — whose first marriage lasted less than a day — has done much more to discredit traditional marriage than gay couples have. (If an aversion to gay unions showed a commitment to traditional marriage, then black America could serve as the model for healthy heterosexual unions. After all, few voting blocs show a stronger antipathy to gay marriage than black voters do. Yet marriage is in decline in black America.) Nor does the Bible bestow a singular blessing on unions between one man and one woman. The marital arrangement most often cited in the Bible is polygamy.
(h/t, Anthony R)