An 8-year-old goes to play at the house of his friend, who is raised by two lesbian women. The environment is a loving one. So this playmate, whose straight parents are married, is going to absorb one of two possible norms.
1) My friend lives in a happy home. His parents are married. When people grow up and love each other, and want to have kids and a happy home, they get married. (I hope I get married one day.)
2) My friend lives in a happy home. His parents aren't married. When people grow up and love each other, and want to have kids and a happy home, sometimes they get married like my parents. Other times they don't get married, like my friend's parents. (One day I may get married and have kids, but maybe I'll just have kids and live with the person I love.)
Friedersdorf's question: Which option, as a conservative, would you prefer to see?
I realize that your first preference might be "women will form relationships with men, not other women, so my 8-year-old won't see such relationships." But that preference is not realistically attainable, even if same-sex marriages are prohibited. (It's true that the majority of women who have relationships with women are in some measure bisexual, but it's a fair bet that the law isn't going to much influence women's decisions on the subject these days or any days in the likely future.) Your second preference might be "lesbian couples shouldn't be allowed to adopt children or have children through artificial insemination," but that too seems highly unlikely regardless of the state of same-sex marriage law. Just as with alcohol consumption, sexual promiscuity, marital disintegration, and the like, many options are off the table given the limits to what law can do, and the limits to what laws are likely to get enacted. Your third preference might be "I won't let my child play at his friend's house, because he'll be exposed to an immoral living arrangement," but I sure hope it won't be, given how cruel it would be to your child and to his friend. (And would you then do the same as to your child's friends whose mothers are living with their boyfriends, or engaged in other forms of what you see as sexual misconduct?)
So it really does come down to encouraging choice 1 and encouraging choice 2 -- and our duty, as thoughtful citizens, to try to choose the best public policies given the suboptimal options we have. Which choice do you think best fosters a pro-marriage mentality on your child's part, even if you think it's extremely likely that your child will himself grow up straight?