Thus, the incest taboo serves to diversify the gene pool of a group because it prohibits sexual relationships between kin, resulting in individuals mating with non-kin. Father-daughter incest is considered the most pathological form of incest, and its persistence often is related to whether the father's partner intervenes. All forms of incest are under-reported, and its incidence is probably far greater than official estimates, largely because of its covert nature and the immaturity and vulnerability of its victims. Certain adults, almost always men, derive sexual gratification through physical and often sexual contact with prepubertal children. Onset is most commonly during middle age, but occasionally during adolescence.
Disorder is characterised by a strong compulsion in attraction towards very young children.
Victims and their family are often known to a paedophile. Most older paedophiles' sexual orientation is heterosexual. Peeping Toms' - repetitive looking at unsuspecting people, usually strangers, who are naked, in the act of undressing or engaged in sexual activity as the usual or exclusive mode of achieving sexual excitement. Element of risk together with anticipated shock on being detected by the person whom they watch, appear to be key components in voyeur's motivation. A disorder which compels an individual to expose himself to another person who is most often shocked or offended by the act.