The institution of marriage is enjoying new popularity - amongst gays.
Left liberals are, though, very reluctant to acknowledge the social and economic benefits of marriage in general. This is highlighted by the AEI where it is pointed out that the concept of two-parent families "May not appeal as much to liberal sensibilities" as the euphemism, "strong" families.
Richard Reeves of the Brookings Institution found that four out of five children who started out in the bottom income quintile—but who were raised by married parents—rose out of the bottom quintile as adults. Meanwhile, kids raised in the bottom quintile to never-married parents had a 50 percent chance of remaining at the bottom. And Brad Wilcox of AEI calculated that 32 percent of the increase in income inequality since 1979 can be linked to the decline in stable, married families.
There are societal changes that we cannot turn the clock back on, and most wouldn't want to. But a growing recognition of the two parent family as the best environment in which to raise children will hopefully lead a return to that structure (not precluding gay parents from my suggestion).