This is what David Blankenhorn is really worried about in The Future of Marriage. There is a concerted campaign to delegitimize the couple-raising-their-children model of marriage and family life. The form of the campaign is, he argues, being most effectively carried on not by a head-on assault, but by side actions. The proponents of The Full Stacey (see my posts of last week) explicitly want to dethrone The Family by placing it on a level with all kinds of families. The effect of this movement, Blankenhorn argues, will not be to broaden the meaning of family, but to deinstitutionalize marriage. When marriage is whatever people want to call a marriage, then there is no public marriage any more.
The core of Blankenhorn's advocacy of marriage for two decades is that it is the best institution for the hard but socially essential business of raising children. He knows, as I do, that any given child might be raised by all sorts of committed adults, and most of those kids will turn out ok. We should honor all those good-enough efforts to raise children as good enough. But the most likely, the most durable, the most efficient, and the most successful option for kids and for society is still to be raised by their own married parents.
I disagree with Blankenhorn about whether same-sex civil unions are too dangerous to legally permit. I think they are good enough. I also don't think there will be many takers, but that does not affect the principle of the thing. I agree with Blankenhorn, though, that any social change that really did deinstitutionalize marriage would be socially disastrous.