• chronic illness;
  • siblings;
  • psychosocial impairment;
  • family rish factors

Summary Focusing on the adjustment of the siblings of three groups of male children; with pervasive developmental disability, diabetes and no known chronic illness, the present study failed to support the view that siblings of ill children are uniformly at greater risk for psychosocial impairment. However, several domains were identified in which siblings as well as parents of ill children were more susceptible to adjustment problems, though ‘risk’ seemed to relate more closely to illness-specific variables than the presence or absence of illness. Several sex differences were found suggesting that same-sexed siblings may be more vulnerable to maladjustment than opposite-sexed pairs. The results are discussed in terms of their implications for investigation and intervention for families with an ill member.