This paper formulates a model to examine the effects of changes in tax-benefit policy on the behavior of divorced parents and the well-being of children in single-parent households. Noncustodial parents choose the level of a child support payment to transfer to custodians. These, in turn, decide over child good expenditures and the allocation of time between market work and parenting. Our main finding shows that welfare policies that subsidize childcare expenditures or reduce withdrawal rates, which are most certainly intended to improve the conditions of working single parents and their children, could actually have the reverse effect. (author abstract)