Many U.S. policymakers support changing the "culture" of poor parents to encourage marriage, work, and religion as a means to end the intergenerational transmission of poverty. In this article Jens Ludwig and Susan Mayer review and evaluate research on how parental work, marriage, and religion affect children's socioeconomic status as adults, as well as on the likelihood that changing these indicators of parental behavior will reduce poverty in the next generation. They conclude that even if policymakers were able to ensure that all children had married, working, and religious parents, the result would be a far smaller reduction in poverty among the children's generation than many people believe. The explanation for this "poverty-prevention paradox," say Ludwig and Mayer, is that the poverty rate in the children's generation depends not only on how many poor children grow up to be poor adults, but also on how many nonpoor children grow up to be poor adults. Reducing the chances that poor children become poor adults will dramatically lower future poverty rates only if most poor adults begin life as poor children. But most poor adults grow up as nonpoor children in the type of "pro-social" households that policymakers are pushing to attain. Moreover, little good evidence supports the idea that such parental behaviors as marriage, work, and religious adherence have strong causal effects on children's long-term economic success. The authors argue that encouraging positive social behaviors in the parents of poor children is a worthwhile goal in its own right. But they stress that policymakers should recognize the limits of this strategy for reducing poverty among future generations. There may be no substitute for a system of social insurance and income transfers for those children who do wind up poor as adults.