The best evidence to date suggests that most or all sexual deviations are learned behaviors, usually through inadvertent or accidental conditioning. There is no convincing evidence to date, suggesting the hereditary transmission of any pathological sexual behavior pattern such as rape, incest, pedophilia, exhibitionism, or promiscuity.
As McGuire explains, as a man repeatedly masturbates to a vivid sexual fantasy as his exclusive outlet (introduced by a real life experience or possibly pornography), the pleasurable experiences endow the deviant fantasy (rape, molesting children, injuring one's partner while having sex, etc.) with increasing erotic value. The [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse] experienced then provides the critical reinforcing event for the conditioning of the fantasy preceding or accompanying the act. (McGuire, R.J., et al., "Sexual Deviation as Conditioned Behavior," Behavior Research and Therapy, 1965, vol 2, p. 185).