Over the last 50 years, the composition and work patterns of the American household have changed dramatically. During this period, the proportion of unmarried and never-married individuals in the population increased steadily as couples chose to marry at later ages and live together prior to marriage. At the same time, the proportion of single-parent households more than doubled. These trends were more pronounced for individuals with lower levels of income and education and for certain racial and ethnic groups. Over the same period, labor force participation among married women nearly doubled.