The prenatal and paranatal records of children with behavior disorders born in Baltimore after 1939 show significantly more complications of pregnancy and delivery, and prematurity than their matched controls. The non-mechanical abnormalities such as toxemia appear to be the important factors in this association rather than the mechanical factors of delivery. These associations are still present even when intellectual and environmental factors are controlled. Hyperactive, confused, and disorganized children have even more of these abnormalities in their background.A hypothesis of a continuum of reproductive casualty is formulated consisting of brain damage incurred during these periods leading to a gradient of injury extending from fetal and neonatal death through cerebral palsy, epilepsy, mental deficiency, and behavior disorder. The implications of this continuum are discussed with regard to further research in the etiology, diagnosis, management, and prevention of these neuropsychiatric disorders.