Questionnaire responses (174 from adoptive parents, 129 from birth parents) measured the relevant factors and parental solicitude on 14 separate scales. The major findings related to the status (adoptive or birth) and sex of the parent. In the birth parent group, mothers tended to be less abusive than fathers, as was expected from the inclusive fitness concept. However, the greater external stress imposed on adoptive mothers, interacting with the absence of inclusive fitness, resulted in an opposite result in the adoptive parent group -- fathers tended to more solicitous than mothers. No overall differences were observed between birth and adopted groups with regard to corporal or sexual abuse. 2 tables, 7 references. (Author abstract modified)