A parent's immigration status influences how a child grows up. That basic finding is grounded in the broad mainstream of current research on childhood development, which has concluded that parental factors can be powerful determinants of their offspring's well being all the way into adulthood. As this report shows, a parent's immigration status matters a great deal. In recent years a great deal of research has examined the ways that having a parent who is an unauthorized migrant influences a child's life. As reviewed in this report, different researchers from different scholarly fields using different data and methodologies have concluded time and again that a parent's unauthorized status imposes a severe penalty on their children. The interrelated findings are most important in weighing the importance of research to the current policy debate. The negative consequences are multiple and severe. Fear of deportation is an important mechanism for inflicting those penalties, and the harm to children can be reversed when the fear of deportation is lifted. A parent's unauthorized status traps a child in a shadowed labyrinth of insecurity and confusion that proceeds from being born and raised American and yet harboring a sense of not belonging. This report provides a review of major findings from dozens of separate studies that have explored those effects in various dimensions of childhood. Available research shows that granting legal status to parents can reverse the harm imposed on their children. Research cited in this report points to the mechanisms by which a parent's legalization can bring improvement in children's life trajectories. Most simply, legalization eliminates the fear and anxiety that can pervade households threatened with the deportation of a parent. Like removing a hobble, this allows a child to ascend developmentally, psychologically and in educational attainment. In addition to the psychological effects, legalization removes the barriers to economic opportunity and social integration that arise from unauthorized status. Even a temporary work permit can set in motion a process that brings economic benefits first to the immigrants, in the form of higher wages, and on to the public sector, in the form of higher tax revenue. It then benefits the nation as a whole, in the form of a more productive labor force. Permission to work of the sort envisioned in the president's executive action provides unauthorized immigrants with a shield against workplace exploitation and the freedom to move across the labor market to find work that best suits their skills. Only one assertion in the immigration policy debate draws unanimous agreement: the endlessly repeated statement that the system is broken. A second assertion worthy of the same accord is that the U.S. citizen children of unauthorized migrants are the most innocent of the many victims of that broken system. They constitute a distinct class of individuals who are defined not by how they have violated regulations but by the fact that the Fourteenth Amendment to the U.S. Constitution guarantees them citizenship, due process, and equal protection.