Three groups of girls who were sexually abused (by either brothers, fathers, or stepfathers) were compared. The purpose was to identify the differing characteristics of the abuse, the family environments, and the psychosocial distress of these children.
Seventy-two girls aged between 5 and 16 were assigned to one of the three groups. Subjects were matched between groups on the basis of their actual age. Children completed measures of traumatic stress; their mothers completed the Child Behavior Checklist-Parent Report Form (CBCL) and other self-report questionnaires on family characteristics. Workers in child protective services completed information regarding the nature and severity of the abuse.
Results suggested few differences in the characteristics of sexual abuse between the three groups. However, penetration was much more frequent in the sibling incest group (70.8%) than in the stepfather incest (27.3%) or father incest (34.8%) groups. Ninety percent of the victims of fathers and brothers manifested clinically-significant distress on at least one measure, whereas 63.6% of stepfather victims did. Compared with father and stepfather perpetrators, brothers were raised in families with more children and more alcohol abuse.
The authors conclude that the characteristics of brother-sister incest and its associated psychosocial distress did not differ from the characteristics of father-daughter incest These findings suggest that theoretical models and clinical practices should be adjusted accordingly and that sibling incest should not necessarily be construed as less severe or harmful than father-daughter incest.