A quantitative examination was made of the association of parental mood and anxiety disorders with severity of disability within a large sample of young children with Pervasive Developmental Disorder (PDD). Maternal recurrent mood disorders were associated with elevated cognitive and adaptive functioning in their affected children, parent reports of increased behavior problems and teacher reports of an internalizing behavioral style. Maternal histories of anxiety disorders and paternal depression or anxiety disorders were not associated with levels of adaptive/cognitive functioning or levels of maladaptive behaviors in the children. Various genetic models are discussed. It is hypothesized that genes associated with recurrent depression in women may exert a "protective" effect on cognition and adaptive functioning in children with PDD.