Paternity and inheritance of wealth

Abstract

One of the oldest conjectures in anthropology is that men transfer wealth to their sister's son when the biological paternity of their ‘own’ children is in doubt1–12. Because maternity is certain, a man is necessarily related to his sister's son and his brother (see Fig. 1). It is argued here that relatedness to male heirs can be assured by passing wealth to sister's sons or down a line of brothers, whether the prevailing kinship system reckons those brothers matrilineally or patrilineally. It is also argued that when several transfers of wealth are considered, a man's likelihood of being cuckolded need not be unrealistically high13 for his successive matrilineal heirs to be more related to him than his successive patrilineal heirs (see Fig. 2). Cross-cultural data on sister's son/brother inheritance14 and frequency of extramarital sex for females15 support the hypothesis that men tend to transmit wealth to their sister's son and/or brother when the probability that their putative children are their genetic children is relatively low.