The California Child Health and Development Studies: twenty years of research.

The Child Health and Development Studies are prospective longitudinal studies of pregnancy and delivery, and of health and development of the children from birth until adolescence. The studies are conducted on members of a prepaid medical insurance plan, and reside in the Oakland area of California, USA. The infants were born in one hospital, between 1659 and 1967. A variety of biomedical studies have been published; these have been summarized in separate sections representing the major research projects. Currently, an adolescent study is in progress in which the older children of the study cohort participate.