adolescence anthropology birthcustoms cross-culturalstudies cultural dorobo gnau(papuanewguineanpeople) initiationrites juvenileliterature kenya languageandculture mauescarpment okiek physical reproduction ritesandceremonies sepikrivervalley(indonesiaandpapuanewguinea) sexcustoms sexualbehavior sociallifeandcustoms symbolism women