This study will examine the joint contributions of schooling and genetic risk to morbidity and mortality. There is considerable evidence linking genes to a broad spectrum of health outcomes. There is also considerable evidence linking schooling to many of the same outcomes. Indeed, there is growing consensus that, of all the features of socioeconomic status, schooling has the strongest and most robust relationship with health. Nevertheless, few if any studies have combined these interests and explored the role of schooling in moderating genetic risk factors. It is time for a more coherent framework for understanding both social and genetic influences. We have recently acquired the largest and most comprehensive cohort study of twins ever conducted in the United States: the National Academy of Sciences-National Research (NAS-NRC) Twin Registry of WWII Military Veterans. The sample size is unusually large. Furthermore, data was collected in three separate panels. The data will be analyzed using the methods of modern behavioral genetics.