Updated September, 2020

I. Definition and Prevalence

            Polygamy and bigamy refer to marriages, or continued conjugal relationships, between more than two persons. In their less common form, polyandry, a single wife has multiple husbands. More frequently, in polygyny, one husband has multiple wives. And there are several different terms for variations on the practice. Sororal polygyny, for example, is where the wives are biological sisters, while hut polygyny is where the wives have separate homes.[i] More common than hut polygyny is patrilocal polygyny, where women leave their family homes to join the home of their future husband in marriage.[ii] Patrilocality, by requiring cowives to cohabitate, imposes significant burdens on a woman’s “privacy . . . honour, reputation, and dignity,” in the view of human rights researchers and lawyers.[iii] Because polygyny, in general, results in a variety of other physical, sexual, and psychological harms to women, it likely qualifies as a harmful practice, or a form of violence against women, under international law.[iv]

            Polygyny was present in 83% of the 849 cultures surveyed by one anthropologist.[v] By comparison, polyandry was found in only four of those groups. To be sure, not every relationship in these cultures is polygynous. However, statistics suggest that in the relevant countries—such as Senegal, for example—most women will end up in a polygynous relationship at some point in their lives.[vi] And the possibility of a relationship turning polygynous can influence the options and incentives facing a woman in a monogamous union. Scholars have identified polygyny as a “sticky” social institution, one that is “persistent over time” within communities.[vii]

            Geographically, polygyny is found in Africa,[viii] the Arab world, Southeast Asia, and parts of the Caribbean.[ix] Polygyny is also practiced, on a smaller scale, in some of the Western countries in which it is officially illegal.[x] Fundamentalist Mormons in the United States are one example. In May 2020, Utah, home to most American Mormons, reduced the criminal penalty for voluntary polygyny.[xi] As an alternative, wealthier men in these countries may also engage in “serial monogamy,” taking multiple, younger wives in succession, thereby “monopolizing the reproductive lifespan of more than one woman without suffering the social stigma of polygamy.”[xii]

II. Causes and Contributing Factors

            The United Nations (UN) has observed that “[i]nequality in the family underlies all other aspects of discrimination against women and is often justified in the name of ideology, tradition and culture.”[xiii] Polygyny falls within this framework. In some communities, multiple wives are considered a measure of a man’s wealth or status, with the resulting competition rendering as many as 40% of marriages polygynous.[xiv] Similarly, men may seek out multiple wives to increase their wealth and number of offspring, using these large family networks to forge familial alliances.[xv] As a result, polygyny is most common among the wealthy, powerful, or high-status men within a country.[xvi] At its extreme, a single powerful man—such as one top military figure in South Sudan—may have over a hundred wives.[xvii]

            Polygyny sometimes has roots in religion. Under Islamic law, for example, a man (but not a woman) may take up to four spouses, so long as he can support them, treats them equally, and supplies a reason.[xviii] Such religious customs may keep polygyny thriving in countries that would otherwise prohibit the practice—for example, the Indian polygyny ban does not apply to Muslims.[xix] And some have converted to Islam precisely to take advantage of these laws.[xx]

            However, not all Muslim countries permit polygyny. In Tunisia, for example, polygyny is outlawed under the very Islamic law that permits it elsewhere; the argument is that it is impossible to truly treat more than one wife equally.[xxi]

            In the past, religious and economic constraints, like Islamic law’s requirement that a husband treat multiple wives equally, have limited polygyny to the wealthy.[xxii] However, globalization has opened the door to a sort of democratization of polygyny. For example, Malaysian couples may get married in neighboring Thailand and then have their marriages recognized in Malaysia—where their marriages would likely not have been originally approved because of the husband’s insufficient means.[xxiii]

III. Consequences

            Polygyny perpetuates patriarchy.[xxiv] One psychologist, who has worked closely with survivors of polygyny, compared the dynamic of “extreme control” present in many polygynous relationships to domestic violence or to a cult.[xxv] Polygynous relationships lend themselves to information asymmetries and opposing spousal incentives, with the husband always at the top of the hierarchy.[xxvi] And legal systems that endorse polygyny often also feature “obedience, modesty, and chastity codes that preclude women from operating as full citizens and enjoying their civil and political rights.”[xxvii]

            Brides in polygynous marriages, who are usually younger and less educated than women in monogamous societies, may experience insecurity, anxiety, anger, depression, and self-esteem issues.[xxviii] They also have difficulty finding their place in the family unit. In one illustrative example, a journalist interviewed a Pakistani judge, who described in detail how equally he treated his wives.[xxix] When one wife entered the room to “give her side of the story,” she was angrily expelled before the journalist could gain her perspective.[xxx] Polygynous marriages—controlled, narrated, and justified by men—denigrate female autonomy. Beyond these psychological effects, polygynous marriages can be dangerous for women, who often have to cope with domestic violence or abuse of their children.[xxxi]

            The UN Committee on the Elimination of Discrimination Against Women (CEDAW) stresses that polygyny is particularly problematic where women have little choice in entering the relationships that are, or may become, polygynous.[xxxii] The shadow of polygyny influences the economic behavior of women, who may try to manage their resources through a sort of “informal insurance” that will guarantee a safe position in case their husbands take additional wives.[xxxiii] In Senegal, for example, women tend to redirect their assets away from household consumption and beyond the husband’s grasp, such as into their own social networks, personal savings, or toward their children’s education.[xxxiv] Polygynous marriages can also lead to competitive environments in which wives are pitted against each other in a race for favor and fortune.[xxxv] This is particularly problematic where the husband has limited resources to support multiple spouses.[xxxvi] Under these circumstances, wives may see cowives as threats, and even try to harm each other or rival heirs.[xxxvii]

            Polygyny has a destabilizing effect on societies, rendering conditions for wives increasingly inferior. Often, husbands must pay a “bride price” to the family of their prospective bride.[xxxviii] As the bride price goes up because demand for women increases, it takes men longer to afford wives. As a result, families will marry their daughters off at younger ages to be able to afford wives for their sons.[xxxix] Where social pressures compel less wealthy young men to turn to illicit means to meet a daunting bride price, women may be caught in the crossfire. Moreover, all of this reinforces a view of women as property, not people.[xl]

            One recent academic study of polygyny practices spanning nearly two hundred countries found a statistically significant relationship between polygyny and domestic violence, sex trafficking, female genital mutilation, and unequal treatment of men and women.[xli] These scholars also considered polygyny’s effect on women’s rights, child brides, children in polygynous households, and governance, while controlling for the level of economic development, a critical variable.[xlii] Ultimately, they conclude that polygyny “will have to be tackled before societies can gain a firm grasp on the challenge of reducing or eliminating violence against women.”[xliii] Relatedly, another study linked polygyny in South Africa to female financial vulnerability, lack of education, and lack of economic empowerment.[xliv]

            Finally, other scholars have linked polygyny to a heightened risk of intergroup conflict. The excess, single men left behind by polygyny are left “young, frustrated, poor, [and] unintegrated,” and often resort to violence as a result.[xlv] In the course of the violence, women are frequently kidnapped, raped, or killed, and their property stolen.[xlvi] Polygyny is a universal theme at the bottom of the Fragile States Index.[xlvii]

IV. Responses

            CEDAW has recently affirmed its position that polygyny violates “a woman’s right to equality with men, and can have such serious emotional and financial consequences . . . that such marriages ought to be discouraged and prohibited.”[xlviii] Similarly, UN Women has called for the total elimination of polygyny.[xlix] The Human Rights Council, Committee on the Rights of the Child, and Committee on Economic, Social and Cultural Rights have all echoed this stance.[l] In so recommending, the UN highlighted the serious financial and emotional consequences for women in polygynous relationships, as discussed above, and called upon member-states to address polygyny on a national legislative level.[li]Advocates urge approaches that take account of the varying systems of marriage, so that a legal solution focused on protecting women from multiple civil law marriages does not leave them stuck in a religious, common law, or other union.[lii]

            Generally, polygyny is governed on a country-by-country basis.[liii] Throughout much of the world, polygyny is illegal—often as the colonial inheritance of British common law or the Napoleonic Code.[liv] Even if it is illegal, unregulated polygynous practices may pose additional problems for women, authorities, and human rights advocates. That still leaves many countries in which polygyny is either legal or the system imposes a middle ground, such as a requirement that existing wives or public officials be noticed (as in Sri Lanka or Egypt) or provide permission (as in Indonesia or Pakistan), or overlapping legal regimes for different marriage types.[lv]

            Prohibiting polygyny, however, is a forward-looking solution, and will not unmake existing unions. Regarding those marriages, CEDAW stresses that prohibiting polygyny must be paired with efforts to protect women in polygynous marriages, particularly economically.[lvi] Complicating matters, UN Women has warned that depriving polygynous marriages of legal validity may threaten wives’ inheritance, child support in case of divorce, or rights to property of the marriage.[lvii] These “transitional concerns” incentivize a thoughtful, individualized approach to phasing out polygyny in each country.[lviii]

            Some defend polygyny by saying their religious beliefs support the practice. However, a Canadian report on polygyny’s various violations of international human rights law argues that belief and practice must be distinguished.[lix] Citing decisions by human rights courts, the report contends that there is latitude for limiting religious practices where they directly interfere with human rights, as in polygyny.[lx]

            Some who study polygyny caution that while proponents deem it a legitimate cultural practice, it is more accurate to view it as a question of “basic human rights.”[lxi] Conceding that prohibiting polygyny may be viewed as imposing Western mores on other cultures, these observers maintain that “[b]y prohibiting polygyny, we reduce social inequities, violence toward women and children, and the proliferation of single men and the violence they perpetuate, as well as increase political rights and civil liberties for all.”[lxii] Phasing out polygyny can help restore dignity, power, security, and autonomy to countless women and