There is almost universal prohibition against sexual relations between certain individuals who are kin. The nuclear family of mother, father, brothers and sisters are prohibited sexual interaction by the taboo but other relatives like uncles, aunts, cousins and steprelatives are also included. Beyond the nuclear family, the exact kin forbidden sexual relationships appear to be culturally determined. All mother's clan may be off limits for example. There are notable exceptions to the incest taboo, for example, the pharoahs of Egypt inbred to keep the royal blood pure 34.
The meaning of incest can be ambiguous. Incest proper usually involves evidence of familial intercourse with orgasm although it may include sex contact such as fondling and touching without vaginal penetration. The latter category is so broad that it can be overinclusive, for example, any kind of intentionally arousing contact to the sexual organs by a family member may be labelled incest15. Some theorists believe children have sexual fantasies toward their parents and a wide range of behaviors may be interpreted as sexual. Once again the criterion of orgasmic outlet clearly defines this sexual problem. However, the presence of a criminal charge may be a more practical criterion of incest since it reflects the existence of a family problem. Moreover incest need not involve a sexual anomaly. In almost 80% of reported cases, intercourse takes place between father and pubescent or post-pubescent daughter53. Only some fathers are pedophilic and have had sexual contact with children other than their own. The second largest reported number of incest cases are between brother and sister (about 20%) whereas mother-son, father-son and multiple relationships explain a minor 2%-to-3% of cases28404143. It would seem that incest usually