A case study was made by interviewing 268 couples who had at home a child they considered severely mentally retarded (IQ 50 or below, age 15 or below). Three kinds of effect were investigated, including general effect, effect of social setting (variables being social-psychological, social-organizational, and demographic-ecological), and joint effect. Results on the nature of family crisis indicated that in families with high early marital integration, the extent of initial impact of retardation on the husband was inversely related to the current degree of integration, and in the remaining families no such relationship was found: mothers were more willing to place a retarded boy who was an oldest child than one who was an only child; retarded boys had a greater impact on fathers initially and on mothers currently; and, especially for husbands, current impact tended to vary directly with initial impact. Results concerning the parents' willingness to institutionalize the child revealed that the higher the social status, the greater the relative willingness of the husband as compared with that of the wife; in high status families, willingness varied directly with the number of normal children in the family; and the lower the social status, the greater the relative willingness of mothers of retarded boys as compared with mothers of retarded girls. (JD)