The last 60 years have seen the emergence of a dramatic socioeconomic gradient in marriage, divorce, cohabitation, and childbearing. The divide is between college graduates and others: those without four-year degrees have family patterns and trajectories very similar to those of high school...

Cohabitation became an acceptable living arrangement for all groups, but cohabitation serves different functions among different groups. The poor and less educated are much more likely to rear children in cohabitating relationships. The college educated typically cohabit before marriage, but...