The status or institution of simultaneous marriage of more than one woman to one man, or of several women to several men. The two forms are polygyny and polyandry. In ordinary use, the term is restricted to polygyny, i.e., where one man is simultaneously married to more than one woman.
Polygamy as polygyny is contrary to divine positive law governing the marriage union (Genesis 2:24; Ephesians 5:31). According to the natural law, even successive polygamy (as in societies that legalize marriage after divorce) hinders the proper care and education of children. And it places an intolerable burden on practicing mutual love between the spouses.
In the Old Testament, God tolerated polygamy for a certain time, as it appears from the examples of men such as Abraham, Jacob, and David. But with the proclamation of the New Law, this concession, almost wrested from by God by reason of the moral obtuseness of man, was revoked. Marriage was restored to its original unity. The language of Christ is very explicit (Matthew 19:3-9; Mark 10:1-12; Luke 16:18). Catholic tradition has consistently interpreted Christ's teaching as absolutely forbidding polygamy, and the prohibition was defined by the Council of Trent, pronouncing anathema against anyone who says that "it is lawful for Christians to have several wives at the same time, and that it is not forbidden by any divine law" (Denzinger 1802). (Etym. Greek polygamos, having many wives.)