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  • One important reason for the rise in polyamory in the U.S. is the on-going decline in marriage and childbearing. Tweet This
  • The relationship instability associated with polyamory will disrupt intact families to the detriment of their children. Tweet This
  • The evidence from the anthropological and historical record suggests that polyamory is unlikely to be viable in the long term. Tweet This
Category: Infidelity

As Kay Hymowitz and Ashley McGuire have both noted in this space, polyamory is having a moment. There is the attention being paid to Molly Roden Winter’s book More, and New York Magazine recently had a “practical guide” to ethical non-monogamy as its cover feature. But support for polyamory is not just coming from elite minority groups. A Pew Research survey last year reported that over half of Americans under the age of 30 say that an open marriage is acceptable. According to a study by the Kinsey Institute, one in nine Americans have already been involved in a polyamorous relationship. 

Older people will recognize polyamory as akin to the free love and wife-swapping of the Swinging Sixties, which was, in part, an expression of the youth culture of the Baby Boom generation, and a rebellion against the traditional mores and strict sex roles of the 1950s. There is some of that cultural rebellion in the current trend toward polyamory. For example, Winter, who has two sons with her husband, complains about a culture that expects mothers to be selfless. She says: “You should have a full self, you shouldn’t have to give yourself up to be a mother. I don’t think that is helpful to children either.”

The Swinging Sixties owed much to the introduction of the birth control pill and the feminist revolution. But this is long in the past. Why is this new trend toward polyamory happening now? Cultural changes have many bases, but one important reason for the rise in polyamory in the U.S. is the on-going decline in marriage and childbearing. The decline in marriage means that a smaller proportion of the population are married, and thus there is proportionately more sexual behavior outside of marriage. The decline in childbearing, both within and outside of marriage, combined with lengthening life expectancy means people have longer periods of their life where they do not have young children in the home. All of this creates a situation that is conducive to polyamory.

The swinging and free love of the 1960s didn’t last, and in the U.S. was followed by the divorce revolution of the early 1970s. What is the likelihood of this new trend of polyamory lasting?

Let’s look at the historical and anthropological evidence. Polyandry, or marriage between one woman and several men, is rare in human societies both now and in the past. According to data from 853 preindustrial societies in Murdock’s Ethnographic Atlas, only 0.5 % permit polyandry.1 The Ethnographic Atlas is a widely used source of information on preindustrial societies, and its data has been found to be reliable and valid. When polyandry occurs, it is often in very poor areas, such as rural Tibet, where the most common form of polyandry is one woman married to two brothers. These are herding societies where one of the brothers is often absent for long periods of time. Even so, many of these marriages are marked with turmoil.

Polygny, or a man with more than one wife or a man with a wife and concubines, has been a fairly stable form of marriage and has been allowed in the majority of pre-industrial societies in the anthropological and historical record. In the sample of the societies referenced above, about 84% permit or prefer polygyny. For example, Old Testament Jews practiced polygyny for thousands of years, and Islamic law allows a man to have up to four wives. In most societies with polygyny, however, women do not have the same rights and status as women in modern societies such as the U.S., and legal codes typically treat women as the property of their male relatives. In a society like ours, where women have economic opportunities and an equal status with men in the eyes of the law, most women are unlikely to accept polygyny (outside of reality TV shows like “Seeking Sister Wife”). So polygyny is unlikely to become the basis of a majority of stable long-term relationships here.

Thus, the anthropological and historical record suggests that polyamory in the form of polyandry or polygyny is unlikely to become the basis of large numbers of long-lasting, stable relationships in a developed country such as ours. But what about some of the more complex arrangements possible under polyamory? The evidence suggests that none of them are likely to last. Part of this is because of human psychology, notably jealousy. Specifically, there is evidence from research in evolutionary psychology that suggests that male sexual jealousy is more powerful than female sexual jealousy. This is far from benign. One study2 that used international data on uxoricide (wife killing) found that it is most frequently committed by husbands who are separated from their wives. Other evidence shows that perpetrators in male-on-female killing are disproportionately intimates (husband, boyfriend, etc.) of the victim, often shortly after the breakup of a relationship. 

Most jealousy does not lead to murder, of course, but such statistics demonstrate the strength of the passion involved and its ability to destroy not just relationships but also lives. The inherent instability of contemporary polyamorous arrangements, and the personal turmoil they can cause, is well illustrated by testimony on the reddit forum r/Polyamory. To get an idea of this testimony, here are a few of the titles I saw when I visited the site: “Introducing my lover and my bestie resulted in disaster for me...,” “Boyfriend doesn’t want to ‘share’ me,” “Partner wants to go on a date while I am sick and have the baby,” and “My partners cheated on me with each other while I was visiting family.”

The relationship instability associated with polyamory will disrupt intact families to the detriment of their children. There is a huge amount of research in sociology that shows that children do best in stable, intact families with two biological parents. All else being equal, children from stable, intact homes are less likely to go to prison, more likely to go to college, more likely to marry, and are less likely to have mental health problems, than children from other home backgrounds. Thus, the breakdown of intact families will negatively affect future generations. As more people suffer from this and other negative consequences of polyamory, it is likely to lose its appeal.  

Thus, the evidence from the anthropological and historical record, as well as evidence of problems associated with polyamory such as jealousy and relationship disruption, suggests that polyamory is unlikely to be viable in the long term, and will go the way of the swinging relationships of the 1960s. This evidence further suggests that polyamory is likely to leave a huge amount of personal chaos, misery, and family ruin in its wake.

Rosemary L. Hopcroft is Professor Emerita of Sociology at the University of North Carolina at Charlotte. She is the author of Evolution and Gender: Why it matters for contemporary life (Routledge 2016), editor of The Oxford Handbook of Evolution, Biology, & Society (Oxford, 2018) and author (with Martin Fieder and Susanne Huber) of Not So Weird After All: The Changing Relationship Between Status and Fertility (Routledge, 2024).      

1. Van den Berghe, P. L. 1979. Human Family Systems. New York: Elsevier.

2. Daly, M., & Wilson, M. (1988). Homicide. Aldine de Gruyter.