This study is a collaborative effort between the U.S. Department of Health and Human Services (including the National Institute of Child Health and Human Development (NICHD), and the National Institute of Environmental Health Sciences at the National Institutes of Health (NIH), and the Centers for Disease Control and Prevention) and the U.S. Environmental Protection Agency. It is the largest study of child and human health ever conducted in the nation, involving recruitment of 105,000 children before birth who will be followed until age 21. This longitudinal cohort study will evaluate gene-environment risk factors for some of the common and rare disorders of childhood including birth defects, preterm birth, obesity, asthma, diabetes, ADHD, autism. The study will also provide a national repository of biological and environmental samples collected periodically across the span of pregnancy and childhood/adolescence. Following the initial startup period, the local coalition will screen and recruit a representative sample of 1000 families in San Diego County beginning in 2009-10.