Jason DeParle of the New York Times:

"...The economic storms of recent years have raised concerns about growing inequality and questions about a core national faith, that even Americans of humble backgrounds have a good chance of getting ahead. Most of the discussion has focused on labor market forces like falling blue-collar wages and lavish Wall Street pay. 

But striking changes in family structure have also broadened income gaps and posed new barriers to upward mobility. College-educated Americans like the Faulkners are increasingly likely to marry one another, compounding their growing advantages in pay. Less-educated women like Ms. Schairer, who left college without finishing her degree, are growing less likely to marry at all, raising children on pinched paychecks that come in ones, not twos.

Estimates vary widely, but scholars have said that changes in marriage patterns — as opposed to changes in individual earnings — may account for as much as 40 percent of the growth in certain measures of inequality. Long a nation of economic extremes, the United States is also becoming a society of family haves and family have-nots, with marriage and its rewards evermore confined to the fortunate classes."