Royal incest and inclusive fitness

Royal incest (mostly brother‐sister; less commonly father‐daughter) represents the logical extreme of hypergyny. Women in stratified societies maximize fitness by marrying up; the higher the status of a woman, the narrower her range of prospective husbands. This leads to a direct association between high status and inbreeding. Royal incest is a fitness maximizing strategy if the following conditions are met: polygyny, patrilineal succession, and parental control of royal succession. Under those conditions, the genetic risks of close inbreeding are more than accounted for by the production of a highly related male heir who has, himself, access to a large harem. Data from Ancient Egypt, Inca Peru, Hawaii, Thailand, Monomotapa, Bunyoro, Ankole, Buganda, Shilluk, Zande, Nyanga and Dahomey confirm hypotheses derived from the sociobiological paradigm of inclusive fitness. [hypergyny, inbreeding, incest, inclusive fitness, polygyny, royalty, sociobiology]