People marry for reasons like companionship, intimacy, economic security, and having children to form a family. Different cultures have various kinship systems that determine inheritance and descent through either the father's or mother's line. Marriages also take different forms such as arranged, child marriages, polygyny where men have multiple wives, or polyandry where women have multiple husbands, each providing benefits to the society that practices them. In the U.S., marriage is primarily monogamous where two consenting partners choose each other.