The interaction of welfare and child support regulations has created a situation in which child support policy's incentives that discourage unwed fatherhood tend to be stronger than its incentives that encourage unwed motherhood. This suggests that more stringent child support enforcement creates incentives that reduce the likelihood of nonmarital childbearing, particularly among women with a significant chance of needing public assistance in the event of a nonmarital birth and their male partners. We investigate this hypothesis with a sample of women from the Panel Study of Income Dynamics, to which we add information on state child support enforcement. We examine childbearing behavior between the ages of 15 and 44 before marriage and during periods of non-marriage following divorce or widowhood. The estimates indicate that women living in states with more effective child support enforcement are less likely to bear children when unmarried, especially if they are young, never-married, or black. The findings suggest that improved child support enforcement may be a potent intervention for reducing nonmarital childbearing. © 2006 by the Association for Public Policy Analysis and Management.