The sexual preferences of incest offenders.

Inclusive fitness theory suggests that discriminative solicitude and inbreeding avoidance are important mechanisms regulating parent-children interactions. From an inclusive fitness perspective, sex with one's biological children is paradoxical. The authors hypothesized that incest can occur when these mechanisms are not activated (e.g., if a father is uninvolved in child rearing) or are overwhelmed by another factor, such as pedophilic interest. They predicted that biological fathers, who presumably have been the most involved in the rearing of their victims, would show greater phallometrically measured pedophilic interest than would other incest offenders against children (e.g., grandfathers, uncles, stepfathers). The prediction was not supported. A testable alternative hypothesis to explain biological father incest is presented and the importance of assessing pedophilic interest among incest offenders is discussed.