Although the nature and severity of a handicapping condition are not the sole determinants of family functioning, the presence of a child with a pervasive developmental disorder has a significant effect on family members. Maternal mental health suffers, and the resulting depression affects her role as mother and marriage partner. Unlike other handicapping conditions with obvious physical stigmata, the invisible handicap of the autistic child and the frequent delay in diagnosis contribute to the mother's self-doubt about her parental competence. While the impact on paternal psychological health is less, the fathers of autistic children are nevertheless highly stressed and appear to be particularly vulnerable to the stress generated by these difficult children. Living within this family climate, the risks for emotional and behavioral problems for siblings must be evaluated, along with their intrinsic strengths, to plan preventive interventions for these children. Effective work with these families requires an understanding of the evolution of family system problems and their dynamic and reciprocal interaction over time.