A Response

I found a blog post arguing against same-sex marriage here, and I commented thusly:
1. While this slippery slope argument raises a common fear among same-sex marriage opponents, I have to agree with Robinson; legalizing same-sex marriage does not automatically legalize polygamous relationships. If polygamists would like to have their relationships recognized under the law, they will have to argue it on it's own merits. Insinuating that polygamy will be legalized because of legalized same-sex marriage is a red herring. It merely distracts from the topic at hand, which is whether same-sex relationships should be recognized by the state. Polygamy is not the same thing.
2. Even people who are known to be infertile would never be discouraged from marrying. It's fallacious to suggest that our society is actually that intent on having every marriage produce children.
Furthermore, your claim that the government only recognizes marriage in order to provide incentive for creating the types of families they want misses the point entirely. The fact is, same-sex couples have families already. They have kids and/or other dependents, and it's in the state's interest to help those families be as stable and healthy as possible by providing legal recognition for their relationships and even tax breaks to ease the raising of children.
And if a single mother and her sister are working together to provide the best possible environment for her child, why shouldn't they have a civil marriage? Having their relationship is recognized by the law doesn't require that they have sex. If the legal aspects of their lives are no different than those of a heterosexual couple, why shouldn't they gain the same legal status and benefits?
3. Once again, same-sex couples already have children, and so it's in the state's interest to provide them with the same benefits that are provided to families headed by opposite-sex couples.
Also, same-sex couples can adopt, and more and more scientific studies are showing that children raised by homosexual couples are just as well off as their heterosexually-raised counterparts. By providing legal recognition to same-sex couples, the state would be providing more opportunities to find loving and supportive families for the state's orphans.
4. One of the biggest problems facing couples with civil unions is that their relationship is often not recognized for what it is. It takes merely a Google search to find stories of loving partners turned away at the hospital because they didn't have their official documents, while their partner lapses into a coma. Or couples harassed at airport security for proof of their relationship with their adopted kids. Civil unions don't cut it; "marriage" is the only term most people understand.
And I do think you make a valid point: the law does normalize our lives. Just as Loving vs. Virginia helped to normalize multi-ethnic marriages, and Laurence v. Texas helped to normalize gay sex, legal same-sex marriage will help to show people that LGBT people can partake in unions that are just as loving and healthy as those of their heterosexual counterparts.
-Chris

PS Schools these days teach kids that marriages of different ethnic backgrounds or different religious backgrounds are ok. Books like "And Tango Makes Three" do the same thing, only for homosexual marriages. Of course, that doesn't prevent you from teaching your kids that homosexual marriages are immoral anymore than it would prevent you from teaching them that Muslim, Jewish, Buddist, or Civil marriages are immoral. The schools teach kids to accept everyone for who they are, but you can still teach them to look down on different types of relationships when they get home.

Lemme know what you think.