Single Mothers, Single Fathers: Gender Differences in Fertility after a Nonmarital Birth.

Research on nonmarital fertility has focused almost exclusively on unmarried mothers, due in part to a lack of fertility information for men. Cycle 6 of the National Survey of Family Growth allows exploration of nonmarital fertility for both genders. We compare the characteristics of unmarried first-time mothers (n = 2,455) and fathers (n = 797), use event history techniques to model second birth hazards, and examine the distribution of men's and women's second births across types of relationships. Our analysis is motivated by questions about how selection into nonmarital fertility relates to subsequent fertility behavior and by theories of mate selection and the "relationship" market. We find that unmarried mothers are more likely to have a second birth than unmarried fathers, driven largely by a higher hazard of having a noncoresidential second birth.