Fosterage, Kinship, and Legend: When Milk Was Thicker than Blood?

When social ties are put to the test, proverbs affirm, those of consanguinity usually prevail: “Blood is thicker than water”; or as Arabs put it, “Blood is thicker than milk” (Lane 1893:1097). These enigmatic adages refer to former institutions of adoptive kinship in western Eurasia, contrasting the blood of natal kinship with the water of baptism or “spiritual kinship” in Christendom, and with infant fosterage or “milk kinship” in Islam. Other sayings, cited as epigraphs above, argue that the nurture of such adoptive kinship may match or supersede natal kinship, just as baptismal sponsorship was supposed to create a spiritual cognation superior to that of mere flesh and blood (Gudeman 1972; Guerreau-Jalabert 1995).