Summary: One important element in estimating the benefits of liberalized migration is the effect on the human capital of migrants' children. Taking human capital benefits of childhood in a developed country into account increases estimates of overall benefits, and may favor permanent migration relative to temporary guest worker programs. I discuss human capital benefits in health, language competence, educational attainment, gender equality, and attachment to location. Benefits are largest and important for immigrants with initially low human capital. Some but not all of these benefits can be attained using retained earnings of temporary migrant workers to help their children at home.