My friend Charles Krauthammer makes the argument succinctly in the Washington Post. "Traditional marriage is defined as the union of (1) two people of (2) opposite gender," he observes. "If, as advocates of gay marriage insist, the gender requirement is nothing but prejudice, exclusion and an arbitrary denial of one's autonomous choices," then "on what grounds do they insist upon the traditional, arbitrary and exclusionary number of two?"Here's the answer. The number isn't two. It's one. You commit to one person, and that person commits wholly to you. Second, the number isn't arbitrary. It's based on human nature. Specifically, on jealousy.
Some people say the Bible sanctions polygamy. "Abraham, David, Jacob and Solomon were all favored by God and were all polygamists," argues law professor Jonathan Turley. Favored? Look what polygamy did for them. Sarah told Abraham to sleep with her servant. When the servant got pregnant and came to despise Sarah, Sarah kicked her out. Rachel and Leah fought over Jacob, who ended up stripping his eldest son of his birthright for sleeping with Jacob's concubine. David got rid of Bathsheba's husband by ordering troops to betray him in battle. Promiscuity had the first word, but jealousy always had the last.
I do like that last sentence and I guess the article makes its point that someone can support one without supporting the other. The problem I see is that he refers to human nature (specifically jealousy) when that's one of the arguments people use against homosexual marriage as well. It is in our nature to hook up with the opposite sex for procreation. Of course, homosexuals often still have the desire to procreate so are they really going "against nature"?
These are my unchecked, early thoughts...feel free to respond.