SINCE the 1960s, the cultural left has launched attack after attack on the conventional nuclear family. In the 1960s and 1970s, the attacks came head on—recall Betty Friedan’s 1963 manifesto, The Feminine Mystique, in which she derided the post-World War II family as a “comfortable concentration camp.” More recently, the attacks have been less direct, but no less serious. Lawyers, journalists, policy makers, and academics have been pushing legal and cultural changes that would elevate a range of relationships— especially cohabitation—to the same status as marriage, thereby effectively abolishing marriage as a meaningful legal and social category.