The Etoro, or Edolo, are a tribe and ethnic group of Papua New Guinea. Their territory comprises the southern slopes of Mt. Sisa, along the southern edge of the central mountain range of New Guinea, near the Papuan Plateau. They are well known among anthropologists because of ritual homosexual acts practised between the young boys and men of the tribe. The Etoro believe that young boys must ingest the semen of their elders daily from the age of 7 until they turn 17 to achieve adult male status and to properly mature and grow strong.

The Etoro believe that they each contain a certain amount of life force, the highest concentrations of which are contained in semen. This life force passes to others through sexual relations. Women are seen to waste the life force if they do not get pregnant after sexual intercourse. As people get older, and their bodies weaken, this is attributed to a depletion of their life force.

O'Neil and Kottak agree that most men marry and have heterosexual relations with their wives. The fear that heterosexual sex causes them to die earlier and the belief that homosexual sex prolongs life means that heterosexual relations are focused towards reproduction.

(http://www.autoadmit.com/thread.php?thread_id=3898030&forum_id=2#35441377)