This continuation of HD 29550 extends our previous studies of the dynamics of nonmarital fertility by inquiring further into the circumstances surrounding a nonmarital first birth, including births to cohabiting couples; by delving more deeply into the processes prior to a premarital first birth; and by opening inquiry into one means by which women may choose to cease childbearing while unmarried. We compare differences in the socioeconomic circumstances of infants born within and outside of marriage and ask if these differences have widened in recent decades. We contrast family stability from the perspective of children born to cohabiting and married parents and identify factors that may explain observed gross differentials. We model the progression from onset of sexual activity to a nonmarital first birth, including estimation of indirect effects of exogenous covariates on nonmarital first birth prevalence. We document how trends in nonmarital fertility for blacks and whites may have been affected by decreases in age at onset of sexual activity intercourse and by increases in age at entry into marriage. We exploit an unusually rich source of data on mothers and children gathered at multiple waves to examine if maternal predictors of offspring entry into sexual activity are mediated by offspring characteristics. We compare parity- and duration-specific rates of contraceptive sterilization for married, cohabiting, and single women to study one means by which cohabiting and single woman may choose to cease childbearing while unmarried. We use a continuous-time competing-risk hazard framework that will permit us to model the nonrandom selection of women into single, cohabiting, and marital statuses. Where feasible, we compare results across multiple data sources, including the March and June Current Population Surveys, the 1979 National Longitudinal Survey of Youth, and the 1988 and 1995 National Surveys of Family Growth.