Is polygamy harmful to society? Scientists believe it may benefit

In July 2025, Ugandan courts quickly rejected a petition challenging its legality polygamyCiting the protection of religious and cultural freedom. For most social scientists and policy makers who have Polygamy has long been declared a “harmful cultural practice”. The decision was a disappointing but predictable setback in efforts to create a healthier and more equal society.

In most cases, polygamy takes the form of one husband and several wives – more accurately called polygamy, which originates from the Greek words “poly” (“many”) and “gyne” (“woman or wife”). The opposite arrangement of one wife and several husbands is called polyandry (from “anar” meaning “man” or “husband”) and is extremely rare throughout the world.

Critics of polygamy present two main arguments. First, they argue that it forces low-status men out of the marriage market, leading to social unrest, crime, and violence against women by frustrated unmarried men. Second, this harms women and children By dividing limited resources among more dependents.

This argument has led prominent political scientist Rose McDermott to describe polygamy as evil. Other researchers, such as anthropologist Joseph Heinrich, even credit Christianity’s ridicule of polygamy as a driving force of Western prosperity.

However, a trio of new studies, relying on the highest standards of data analysis, argue that these arguments are misguided.

I have spent my career working at the intersection of anthropology and global health, researching how and why family structure varies – and what this diversity means for human well-being. Much of this work has been done in collaboration with colleagues tanzania where, like ugandaPolygamy is relatively common. This new wave of work underscores the value of our research, effectively demonstrating that good intentions and intuition are no substitute for cultural sensitivity and evidence.

Does polygamy deprive men of marriage?

A new study published in October 2025 in the Proceedings of the National Academy of Sciences offers the first comprehensive, large-scale analysis of polygamy and men’s marriage prospects. The project is a collaboration between demographer Hampton Gaddy and evolutionary anthropologists Rebecca Sear and Laura Fortunato.

The researchers used demographic modeling and an extraordinary trove of census data – more than 84 million records from 30 countries in Africa, Asia and Oceania, as well as the entire U.S. Census from 1880, when polygamy was practiced in some American communities. They demonstrate that polygamy does not exclude large numbers of men from marriage. In fact, in many contexts, men are actually more likely to marry where polygamy is common than where it is rare.

The narrative that polygamy makes bachelors lonely makes intuitive sense. In a community with equal numbers of men and women, if one man marries two wives, the other man must remain celibate. Extend this to an entire society, and polygamy looks like a recipe for an army of angry, single men.

Parallel arguments have been made about the rise of incel – A depiction of the “involuntary” and “celibate” subculture within monogamous countries, including the US, the argument being that higher-status men leave lower-status men lustful and depressed, ultimately leading to violence.

The trouble is that the actual demography is not that simple. Women generally live longer than men, men often marry younger women, and populations in many parts of the world are aging, ensuring that younger spouses are available for older partners. These factors, which are characteristic of many contemporary African countries, tilt the marriage market towards an overabundance of women. Under many realistic circumstances, a large proportion of men can have multiple wives without causing trouble to their partners.

In fact, in about half of the countries examined, higher rates of polygamy were associated with fewer, not more, unmarried men. Only a few countries showed the expected positive relationships, and even then were inconsistent over time.

The case of historic Mormon communities in North America is equally revealing. When researchers compared counties with Mormon polygamy documented in the 1880 census to others, they found lower rates of unmarried men in polygamous areas. Gaddy and colleagues argue that this is explained by the tendency for cultural norms to view polygamy as relatively procreative, thereby increasing marriage rates for all.

Do women and children get a smaller share?

What about the argument that polygamy harms women and children by distributing property owned by men among more people? There are certainly studies that have demonstrated a link between polygamy and poor health. But another school of thought argues that correlation should not be equated with causation.

Ten years ago, my colleagues and I compared results from more than 50 villages in Tanzania to document that polygamy is associated with higher food insecurity and poor child health. However, this pattern was an artifact of polygyny which is most common among marginalized Maasai communities, who live in drought-prone areas with inadequate health care. Furthermore, when families are compared within communities, polygamous families are generally more wealthy, which is an important factor in making polygamy attractive to women, and children are not harmed.

Replicating these results, anthropologist Riana Minocher and colleagues recently published a study that uses a detailed, longitudinal dataset from a 20-year prospective study in another region of Tanzania. Analyzing the survival, development, and education of thousands of children, they found no evidence that monogamous marriage is beneficial.

Together, these results support a theory known as the polyvalent threshold model. Simply put, provided women have choices in marriage, sharing a husband is unlikely to be economically harmful, as they will prefer to marry men with enough wealth to offset any costs. This scenario may not fit all contexts, but these studies clearly undermine claims that polygamy is clearly harmful.

Hidden benefits of polygamy

A more recent study, published in August 2025 by economist Sylvain Desy and colleagues, suggests that polygamy has unrecognized advantages in difficult times.

Based on crop yield data from more than 4,000 farming households across Mali, census data on marriage patterns, and detailed meteorological records, they found that in villages where polygamy is rare, drought dramatically cuts harvests. But in villages where polygamy is common, this blow is softened.

Researchers argue that polygamous marriage, by increasing the number of in-laws, creates stronger networks of social support. Furthermore, since wives often came from different villages and regions, their extended relatives were in a good position to send food, money, or labor when local crops failed. Such support helps explain both the resilience of polygamous communities during drought and the continued endurance of the marriage practice from one generation to the next.

So, is polygamy harmless?

These studies do not mean that polygamy is harmless. In fact, allowing men but not women to have multiple spouses is clearly inequitable and linked to patriarchal ideology that views women as subordinate or inferior to men. For example, recent studies have shown that intimate partner violence is more likely to occur in polygamous marriages.

About the author

In short, there are many ways in which polygamy can be harmful.

Nevertheless, the best evidence suggests that polygamy is unlikely to be the root cause of social unrest. Furthermore, in pervasive patriarchal systems that afford few women, regardless of marital status, economic and social security, polygamy may be not only a tolerable option, but in some contexts a preferred arrangement with concrete benefits for both sexes.

Simplistic stories about the dangers of polygamy may be compelling and intuitive, but they risk misleading the public, reinforcing stubborn notions of Western cultural superiority, and hindering effective global health policy by sidelining more relevant initiatives. Building healthy societies requires paying attention to the evidence and being open to the possibility that all family structures have the potential to cause harm.