Polygamy, literally many marriages in ancient Greek, 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). The term is often used in a de facto sense, applying regardless of whether such marriages are legally recognised.
Polygamy vs. bigamy
Polygamy is the anthropological term, which can be either polygyny (one man having multiple wives) or polyandry (one woman having multiple husbands). Historically, both practices have been found, but polygyny appears far more commonly than polyandry.
Bigamy is the term used by law when someone has entered into any number of "secondary" marriages in addition to one legally-recognized marriage. Many countries have specific statutes outlawing bigamy, making any secondary marriage a crime. When a man with three wives is charged, for example, he is charged with two counts of bigamy, for the two "secondary" marriages after the first one.
The most famous example of polyandry in Hindu culture occurs in the Mahabharata, where the Pandavas are married to one common wife, Draupadi. Today it is almost exclusively observed in the Toda tribe of India, where it is sometimes the custom for several brothers to have one wife. In this context, the practice is intended to keep land (a precious resource in a populous country like India) within the family.
Polygamy vs. polyamory
Main article: Polyamory.
The term polyamory has recently come to refer to romantic or sexual relationships involving multiple partners at once, regardless of whether they involve marriage. Although any loving polygamous relationship could also be considered polyamorous, and some polyamorous relationships involve multiple spouses, usage tends to distinguish between the words: "polygamy" is more often used to refer to codified forms of multiple marriage (especially those with a traditional/religious basis), while "polyamory" implies a relationship defined by negotiation between its members rather than cultural norms.
Polygamy vs. group marriage
Main article: Group marriage.
Most polygamous relationships are either polygynous or polyandrous, but not both at once. This dictates a structure in which, while one person may have multiple spouses, none of those spouses will be married to anybody else. Combining polygyny and polyandry allows relationships in which such spouses may themselves have other spouses; such marriages are culturally distinct from most forms of polygamy (and, comparatively, rare).
Polygamy vs. poly relationship
Main article: Poly relationship.
While polygamy is sometimes mistakenly confused with other forms of nonmonogamy, it is not the same thing. Such other forms of nonmonogamous relationships are discussed at poly relationship.
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"  (http://www.econ.ucsb.edu/~tedb/Evolution/polygyny3.pdf) (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 monogamy.
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
The Greco-Roman society in which early Christianity developed was at least formally monogamous, yet the Old Testament clearly demonstrates polygamy among the Biblical patriarchs. Saint Augustine demonstrated this conflict in his consideration of Old Testament polygamy in The Good of Marriage (chapter 15, paragraph 17), where he wrote 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 declined to judge the patriarchs, but did not deduce from their practice the ongoing acceptability of polygamy. 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]."
Today, the Catholic Church clearly condemns polygamy; 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." Also in paragraph 1645 under the head "The Goods and Requirements of Conjugal Love" states "The unity of marriage, distinctly recognized by our Lord, is made clear in the equal personal dignity which must be accorded to man and wife in mutual and unreserved affection. Polygamy is contrary to conjugal love which is undivided and exclusive."
Periodically, Christian reform movements that have aimed at rebuilding Christian doctrine based on the Bible alone (sola scriptura) have at least temporarily accepted polygamy as a Biblical practice. During the Protestant Reformation, Martin Luther advised Philip of Hesse that although he found nothing unbiblical about polygamy, he should keep his second marriage a secret to avoid public scandal. The radical Anabaptists of Münster also practiced polygamy, but they had little influence after the defeat of the Münster Rebellion in 1535. Other Protestant leaders including John Calvin condemned polygamy, and at any rate sanctioned polygamy did not survive long within Protestantism.
Although classical Jewish literature indicates that polygamy was permitted, the various segments of Judaism have now outlawed polygamy. The first was Ashkenazi Jewry, which followed Rabbenu Gershom's ban since the 11th century. Some Sephardi groups only discontinued polygamy much more recently, to the point that the State of Israel had to make provisions for polygamic families immigrating after its 1948 creation.
Islam allows a man to have up to four wives at any one time. However, a woman cannot have more than one husband at a time. The Qur'an in verse 4:3 states:
"And if you fear you shall not be able to deal justly with the orphan girls, then marry (other) women of your choice; 2, 3 or 4, but if you fear you may not be able to deal justly (with them) then only one." (English translation by Dr Muhammad Taqi-ul-Din Al Hilali and Dr Muhammad Muhsin Khan).
This verse is linked to the preceding verse which relates to a man taking an orphaned girl as his wife. The caregivers of these orphan girls have an unfair advantage (especially during the time during which the Qur'an was revealed) over them if they wish to marry them. Being their guardians, they may be tempted to marry them without paying them their full dowries or in order to confiscate their inheritance. This verse is telling these men that if they fear that they cannot deal justly with the orphans whom they wish to marry, then they should marry other women (not orphaned women but free women with guardians and families who can look over and protect their rights).
It's important to note the context within which the term 'orphan girls' is being used here. Orphaned girls (that is, orphaned of both mother and father as well as any immediate family to look after them) at the time when the Qur'an was revealed had very low status in society and virtually no recognisable rights, unless a caregiver chose to take them in. The relationship of the caregiver to the orphaned girl would have to satisfy the criteria set out in the Qur'an verses 4:23 and 4:24 as to which women a man is permitted to marry under Islamic law in order for verse 4:3 to be valid.
Some Muslims, however, believe that polygamy is restricted (e.g.  (http://www.answering-christianity.com/polygamy.htm)). They quote the following verse 4:129 "Ye are never able to be fair and just as between women, even if it is your ardent desire: But turn not away (from a woman) altogether, so as to leave her (as it were) hanging (in the air). If ye come to a friendly understanding, and practise self-restraint, Allah is Oft-forgiving, Most Merciful." (Yusuf Ali translation.) This, combined with the requirement for fairness stated in 4:3 and arguments based on its context, has led them to conclude that polygamy is only sanctioned in exceptional circumstances - e.g. when there is a shortage of male adults after a war - and that monogamy is generally preferable. Opponents of this view believe that verse 4:129 does not seek to discourage polygamy, but instead guides the husband on how to treat his wives fairly in practice, even though he's not fair to them in terms of not loving them equally.
In Hinduism, polygamy was practiced since ancient times. Hinduism does not prohibit polygamy but does not encourage it. Historically, only kings, in practice, were polygamous. For example, the Vijanagar emperor, Krishnadevaraya had multiple wives. In modern times, polygamy is prohibited under Indian law, specifically under those provisions which relate to Hindu marriage. However, Muslims in India are allowed to have multiple wives. As of October 2004, Muslims and Hindus are treated differently under Indian law. There have been efforts to propose a uniform marital law that would treat all Indians the same, irrespective of religion.
Early in its history The Church of Jesus Christ of Latter-day Saints practised polygamy in the United States and referred to it as "plural marriage". It was publicly taught by the Church in 1852, and was a sacred ordinance. Only some members of the Church practiced polygamy. The practice was introduced by Brigham Young after the assassination of Joseph Smith, the Church's founder.
The practice of polygamy quickly led to persecution of the Church and the enacting of anti-polygamy laws. (The U.S. Congress made the practice illegal in U.S. Territories in 1862). Many members of the Church fled to Canada in an attempt to set up communities free from prosecution; for example, Cyril Ogston founded Seven Persons, Alberta. 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 anti-polygamy legislation stripped Church members of their rights as citizens, disincorporated the Church, and permitted the seizure of Church property until the Church ordered the discontinuance of the practice in 1890.
National attention in the United States again focused on potential polygamy among the Church 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). This caused 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 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 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.
Another major concern has recently arisen with the discovery that many women are brought into these polygynous relationships prior to the age of consent, meaning that some men may be committing statutory rape. Many modern polygamists and polyamorists deliberately classify "plural marriage" as wholly separate from other forms of polygamy.
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.
Current proponents and critics
Authors such as David Friedman and Steve Sailer have argued that, counterintuitively, polygamy tends to benefit most women and disadvantage most men. Friedman uses this observation to argue in favor of legalizing polygamy, while Sailer uses it to argue against legalizing it.
The Libertarian Party defends complete decriminalization of polygamy.
Individualist feminism and advocates such as Wendy McElroy also supports the freedom for adults to voluntarily enter polygamous marriages. In contrast, radical feminism has generally aligned with Christian fundamentalists to stop polygamy. Some Human Rights Activists see polygamy as an abuse issue based on law and not one that is related to religion but rather one that is hidden behind the veil of religion. The offcial LDS Mormon church also generally supports enforcing laws against polygamy.
Those who advocate a Federal Marriage Amendment to prohibit same-sex marriage generally word their proposed laws to also prohibit polygamy.
Robert Heinlein was a science fiction writer who discussed polygyny, polyandry, group marriage, and line marriage in his works.
Compare monogamy and concubinage.
Multiple divorce and marriage for polygamy
While most polygamists do not support the idea, a small minority of polygamous families use a system of multiple divorce and legal marriage. This is where the husband marries the first wife, she takes his last name, he divorces her and then marries the next wife who takes his name. [For polyandry relationships, it is the wife that marries and divorces the husbands one after another.] This is repeated until he has married and divorced all his wives, except possibly the last one. This way the wives feel justified in calling themselves Mrs. [husband's last name] and, while legally they're divorced from the husband, they act still married to him and expect those around them to acknowledge and respect this.
Since only one wife is married to the husband at any one time, no law was being broken and so this type of polygamous family unit could be overt about their relationship. In 2001, however, the state of Utah convicted Tom Green of criminal non-support and four counts of bigamy for having 5 serially monogomous marriages, while living with previous legally divorced wives. Having used that system of multiple divorce and marriage to defraud the state's welfare system, his cohabitation was considered evidence of a common-law marriage to the wives he had divorced while still living with them. That premise was subsequently affirmed by the Utah Supreme Court in State v. Green (http://www.utcourts.gov/opinions/supopin/greeni090304.htm), as applicable only in the State of Utah. It was Green's crime of criminal non-support which initiated the case in that one state. As that case applies only to Utah, it is therefore not a nationwide precedent on common-law marriage and polygamy. However, it does show the risks in using the system of multiple divorce and legal marriage and why many polygamists avoid it.
- Pro-Polygamy.com (http://www.pro-polygamy.com) - Provides timely op-eds and press releases on polygamy-related current events for the secular mass media
- MormonPolygamy.com (http://www.mormonpolygamy.com) - A group of Mormon women called "Principle Voices of Polygamy"
- The history (http://www.christianpolygamy.info/history/) of the "Christian polygamy (http://www.christianpolygamy.info)" movement (http://www.christianpolygamy.info/movement/) - Presents the history of the new, modern social movement which has no connection to Mormon polygamy.
- TruthBearer.org -- Organization for Christian polygamy (http://www.truthbearer.org) Provides activists with teachings, resources, and media interviews (http://www.truthbearer.org/media/)
- Biblical Polygamy (http://www.biblicalpolygamy.com) - Presents biblical exegesis of arguments to support polygamy and lists out all the polygamists in the Bible
- A defence of Christian polygamy (http://www.samchapman.f2s.com/polygamy.htm) - discusses and answers objections many Christians have to polygamy with cited evidence in the Bible
- Another defense of Christian polygamy (http://www.polygamy.net/)
- When is polygamy allowed in Islam? (http://www.answering-christianity.com/polygamy.htm) - from a Muslim point of view
- Anti-Polygamy.org (http://www.anti-polygamy.org) - Analyzes anti-polygamy rhetoric and arguments.
- Anti-Polygamy.com (http://www.anti-polygamy.com) - A discussion forum for both sides of the anti-polygamy debate.