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.

This is a really unfortunate trend:

"Married couples are having children later than they used to, divorcing less and investing heavily in parenting time. By contrast, a growing share of single mothers have never married, and many have children with more than one man."