as an aid to hygiene where regular bathing was impractical; as a means of marking those of higher social status; as a means of humiliating enemies and slaves by symbolic castration; as a means of differentiating a circumcising group from their non-circumcising neighbors; as a means of discouraging masturbation or other socially proscribed sexual behaviors; as a means of increasing a man's attractiveness to women; as a demonstration of one's ability to endure pain; as a male counterpart to menstruation or the breaking of the hymen; to copy the rare natural occurrence of a missing foreskin of an important leader; as a way to repel demonesses; and/or as a display of disgust of the smegma produced by the foreskin. Removing the foreskin can prevent or treat a medical condition known as phimosis. It has been suggested that the custom of circumcision gave advantages to tribes that practiced it and thus led to its spread. Darby describes these theories as "conflicting", and states that "the only point of agreement among proponents of the various theories is that promoting good health had nothing to do with it." Freud believed that circumcision allows senior men to constrain the incestuous desires of their juniors, and mediates the tension inherent in the father-son relationship and generational succession. Youth are symbolically castrated, or feminized, but also blessed with masculine fruitfulness. Prior to the Out of Africa migration, circumcision may have been a cultural practice among homo sapiens. Homo sapiens then migrated out of Africa. In 45,000 BP, modern humans migrated into Australia. Based on iconographic evidence and perceived retention of hunter-gather traits among Australian Aborigines that are associated with the Paleolithic, circumcision may have originated in the early period of the Paleolithic, and may have even been an evolutionary trait of homo sapiens. In 40,000 BP, homo sapiens migrated into Europe. Upper Paleolithic rock art from the Aurignacian (38,000 BP – 30,000 BP), Gravettian (30,000 BP – 22,000 BP), Solutrean (22,000 BP – 18,000 BP), and Magdalenian (18,000 BP – 11,000 BP) eras of Prehistoric Europe feature figures with male genitalia that may serve as evidence of groups practicing male circumcision or the retraction of penile foreskins. Ancient world Ancient Africa North Africa At Oued Djerat, in Algeria, engraved rock art with masked bowmen, which feature male circumcision and may be a scene involving ritual, have been dated to earlier than 6000 BP amid the Bubaline