Between 1990 and 2000, Norway's out-of-wedlock birthrate rose from 39 to 50 percent, while Sweden's rose from 47 to 55 percent. In Denmark out-of-wedlock births stayed level during the nineties (beginning at 46 percent and ending at 45 percent). But the leveling off seems to be a function of a slight increase in fertility among older couples, who marry only after multiple births (if they don't break up first). That shift masks the 25 percent increase during the nineties in cohabitation and unmarried parenthood among Danish couples (many of them young). About 60 percent of first born children in Denmark now have unmarried parents. The rise of fragile families based on cohabitation and out-of-wedlock childbearing means that during the nineties, the total rate of family dissolution in Scandinavia significantly increased.

Scandinavia's out-of-wedlock birthrates may have risen more rapidly in the seventies, when marriage began its slide. But the push of that rate past the 50 percent mark during the nineties was in many ways more disturbing. Growth in the out-of-wedlock birthrate is limited by the tendency of parents to marry after a couple of births, and also by the persistence of relatively conservative and religious districts. So as out-of-wedlock childbearing pushes beyond 50 percent, it is reaching the toughest areas of cultural resistance. The most important trend of the post-gay marriage decade may be the erosion of the tendency to marry at the birth of a second child. Once even that marker disappears, the path to the complete disappearance of marriage is open.

And now that married parenthood has become a minority phenomenon, it has lost the critical mass required to have socially normative force. As Danish sociologists Wehner, Kambskard, and Abrahamson describe it, in the wake of the changes of the nineties, "Marriage is no longer a precondition for settling a family--neither legally nor normatively. . . . What defines and makes the foundation of the Danish family can be said to have moved from marriage to parenthood."