Adelphogamy is a form of marriage in which brothers share and cohabit with one or more wives. Marriage between a brother and sister is also called adelphogamy in certain societies. It is a term used synonymously for Fraternal polyandry.
Adelphogamous relationships are banned by law in many societies and are considered morally wrong in modern cultural institutions. The cultural framework of most societies is molded to prevent such relationships in the contemporary era. However, such practices continue to exist in certain aboriginal tribes and primitive cultures.
Such a mating method among humans and animals is also a topic of study for anthropologists, sociologists, and zoologists.