This entry examines the legal-ethical rules and practices, prevalent in Muslim societies, past and present, which stem from the idea that transmission of milk from a nursing woman to a strange (that is, another woman's) nursling creates impediments to marriage.

The idea that the relations created through lactation between a nurse and her (strange) nursling are similar, from the viewpoint of prohibitions of marriage, to blood relations, is based on a pre-Islamic Arabic concept. In Arabic medical writings of the classical period of Isla…