The U.S. child poverty rate has fluctuated between 15 and 23 percent for the past four decades, but far more children–37 percent–live in poverty at some point during their childhoods. Being poor at birth strongly predicts future poverty status. Using the PSID, this study finds that 49 percent of children who are poor at birth go on to spend at least half their childhoods living in poverty. In addition, children who are born into poverty and spend multiple years living in poor families have worse adult outcomes than their counterparts in higher-income families.