Cohort Estimates of U.S. Nonmarital Fertility

Lawrence L. Wu, New York University

This paper presents cohort estimates of nonmarital fertility for U.S. women born between 1915 and 1965. Our knowledge about historical trends in nonmarital fertility is based heavily on period estimates of the proportion of births occurring outside of marriage. Such estimates say little about changes in nonmarital childbearing for successive birth cohorts of women. This paper seeks to fill this notable omission in the literature. I use retrospective fertility and marital histories for U.S. women in the June 1980, 1985, 1990, and 1995 Current Population Surveys to provide estimates of cohort trends in: completed nonmarital fertility, subsequent nonmarital fertility given a nonmarital first birth, and patterns of nonmarital fertility for those women who bear children both within and outside of marriage. I contrast cohort and period trends, and show how estimates vary under alternative definitions, for example, births that occur between separation and the formal dissolution of a marriage.