Polygamy is a marital practice in which a person has more than one spouse simultaneously (as opposed to monogamy where each person has a maximum of one spouse at any one time). Recent commentators use the term polyamory to refer to romantic or sexual relationships involving multiple partners at once; it need not involve marriage. Bigamy is polygamy with a person having two partners (not more).

Polygamy may or may not involve group sex.

Table of contents
1 Types of Polygamy
2 Polygamy Worldwide
3 Patterns of Occurrence
4 Polygamy and Religion
5 Legal Situation
6 Mormon Polygamy

Types of Polygamy

Polygyny refers specifically to one man having multiple wives, and polyandry to one woman having multiple husbands. Historically, both practices have been found in many cultures, but polygyny appears far more commonly than polyandry. Combinations such as multiple men officially married to multiple women, or a man with two wives, one of whom has also another husband, seem even more rare or nonexistent. Currently no official polygamous same-sex marriage is possible.

Polygamy Worldwide

Polygynous societies are about four times more numerous than monogamous ones. In 1994, Theodore C. Bergstrom noted in his paper "On the Economics of Polygyny" [1] (U. Mich. Center for Research on Economic and Social Theory, Working Paper Series 94-11) that "Although overt polygamy is rare in our own society, it is a very common mode of family organization around the world. Of 1170 societies recorded in Murdock's Ethnographic Atlas, polygyny (some men having more than one wife) is prevalent in 850.

Patterns of Occurrence

At the same time, even within societies which allow polygamy, the actual practice of polygamy often occurs only rarely. To take on more than one wife often requires considerable financial resources: this may put polygamy beyond the means of the vast majority of people within those societies. Such appears the case in many traditional Islamic societies, and in Imperial China

Within polygamous societies, multiple wives often become a status symbol denoting wealth and power. Conversely, within societies which formally prohibit polygamy, social opinion may look favorably on persons maintaining mistresses or engaging in serial polygamy.

Some observers detect a social preference for polygyny in disease-prone (especially tropical) climates, and speculate that (from a potential mother's viewpoint) perceived quality of paternal genes may favour the practice there. The countervailing situation allegedly prevails in harsher climates, where (once again from a potential mother's viewpoint) reliable paternal care as exhibited in monogamous pair-bonding outweighs the importance of paternal genes.

Polygamy and Religion

Few pronouncements of the early Christian church explicitly prohibit polygamy, since the practice appeared very uncommonly in Graeco-Roman society. Early Christians desired to condemn polygamy, because it conflicted with the prevailing mores of the Graeco-Roman society in which they lived; yet at the same time they had to explain the clear permission given for it in the Old Testament. Saint Augustine demonstrates this conflict in his consideration of the polygamy practiced in the time of the Old Testament patriarchs when he writes in The Good of Marriage (chapter 15, paragraph 17) that though it "was lawful among the ancient fathers: whether it be lawful now also, I would not hastily pronounce. For there is not now necessity of begetting children, as there then was, when, even when wives bear children, it was allowed, in order to a more numerous posterity, to marry other wives in addition, which now is certainly not lawful." He declines to judge the patriarchs, but he certainly makes the current illegality relatively clear. In another place, he wrote, "Now indeed in our time, and in keeping with Roman custom, it is no longer allowed to take another wife, so as to have more than one wife living [emphasis added]."

The Catholic Church clearly condemns polygamy today; the Catechism of the Catholic Church lists it in paragraph 2387 under the head "Other offenses against the dignity of marriage" and states that it "is not in accord with the moral law." Most Christian churches of any denomination condemn polygamy. Splinter groups of the Church of Jesus Christ of Latter-Day Saints, some other small non-LDS Christian groups in the United States, and some African Christians, however, practice polygamy.

Legal Situation

Secular law in most "Western" countries with large Jewish and Christian populations does not recognise polygamous marriages. However, few such countries have any laws against living a polygamous lifestyle: they simply refuse to give it any official recognition. Parts of the United States, however, criminalise even the polygamous lifestyle, which is unusual; these laws originated as anti-Mormon legislation, although they are rarely enforced.

Mormon Polygamy

The early Church of Jesus Christ of Latter-day Saints in the United States practised polygamy and referred to it as "Plural Marriage". It was publicly taught by the Church in 1852, and quickly led to persecution of the Latter-day Saints and the enacting of laws against its practice (the United States Congress made the practice illegal in U.S. Territories in 1862). Although Latter-day Saints believed that their religiously-based practice of plural marriage was protected by the United States Constitution, opponents used it to delay Utah statehood until 1896. Increasingly harsh antipolygamy legislation stripped Latter-day Saints of their rights as citizens, disincorporated the Church, and permitted the seizure of Church property before the Church ordered the discontinuance of the practice in 1890.

National attention in the United States again focused on potential polygamy among the LDS in the early 20th century during the House hearings on Representative-elect B. H. Roberts and Senate hearings on Senator-elect Reed Smoot (the Smoot Hearings), which caused the Church President Joseph F. Smith to issue his "Second Manifesto" against polygamy in 1904. Since that time, it has been Church policy to excommunicate any member either practicing or openly advocating the practice of polygamy.

The ban on polygamy resulted in a schism within the Church, with various splinter groups leaving the Church in order to be able to continue the practice of polygamy. Polygamy among these groups persists today in Utah and neighboring states, as well as among isolated individuals with no organized church affiliation. Polygamists of this kind are sometimes called "Mormon fundamentalists", despite their lack of affiliation with the mainstream LDS Church. This contemporary polygamy is estimated to be practiced by about 30,000 people. Most of the polygamy is believed to be restricted to about a dozen extended clans.

The practice of informal polygamy among these groups presents itself with interesting legal issues. It has been considered difficult to prosecute polygamists partly because they are not formally married under Utah law. Without evidence that suspected offenders have multiple, formal or common-law marriages, these groups are merely subject to the laws against adultery or unlawful cohabitation. These laws are not commonly enforced because they also criminalize other behavior that is otherwise socially sanctioned.

Compare monogamy and concubinage.