Newsweek magazine's cover story on December 15, 2008, read "The Religious Case for Gay Marriage." It featured an article by religion editor Lisa Miller entitled, "Our Mutual Joy," in which she attempted to argue a biblical case for gay marriage.
There have been several prominent scholars and theologians who have responded to this piece in length. Kevin Lewis, Christian apologetics professor at Biola University, has written an article which you can read here. Dr. Albert Mohler, president of The Southern Baptist Theological Seminary, has responded here. The Family Research Council has also posted a point-by-point rebuttal on their blog which you can read here.
As these articles show, liberals must constantly take passages out of context, undercut Scripture, and resort to fallacious reasoning in endeavoring to make their point. If proponents of same-sex marriage want to defend their case, fine. Muster your best arguments and present them in public debate. But let us not resort to intellectual dishonesty, bad logic, and poor hermeneutics in an effort to distort the clear teaching of Scripture.