Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/33291
Title: High rates of polygyny do not lock large proportions of men out of the marriage market
Authors: Gaddy, H
Sear, R
Fortunato, L
Issue Date: 3-Oct-2026
Publisher: National Academy of Sciences
Citation: Gaddy, H., Sear, R. and Fortunato, L. (2025) 'High rates of polygyny do not lock large proportions of men out of the marriage market', Proceedings of the National Academy of Sciences of the United States of America, 122 (40), e2508091122, pp. 1–9. doi: 10.1073/pnas.2508091122.
Abstract: There is a widespread belief, in both the scholarly literature and the popular press, that polygyny prevents large numbers of men from marrying by skewing the sex ratio of the marriage market. In turn, the exclusion of men from marriage is thought to lead to negative outcomes, e.g., by fueling crime and armed conflict. In this paper, we investigate systematically the relationship between polygyny and men’s marriage prospects. First, using a demographic model, we show that marriage markets are skewed sufficiently feminine, under a range of realistic demographic scenarios, to sustain some level of polygyny without locking any men out of marriage. Second, through analysis of 84.1 million census records from 30 countries across Africa, Asia, and Oceania between 1969 and 2016, we show that the subnational association between the prevalence of polygyny and the prevalence of unmarried men is negative or null, rather than positive, for almost all countries in the sample. Third, through analysis of the full-count 1880 US federal census, we show that the average prevalence of unmarried men is lower, not higher, across counties of the West with Mormon polygyny, compared to other counties of the West, and to counties of the Midwest and the Northeast; it is higher only compared to counties of the South. Overall, these findings challenge a dominant narrative linking polygyny to negative social outcomes. Drawing on existing evidence, we suggest that the observed patterns may be explained by an underlying association between the prevalence of polygyny and the strength of promarriage norms.
Description: Significance: Social scientists often assume that when men can marry multiple wives (polygyny), many other men will be unable to marry. Versions of this assumption feature prominently in theories of civil war, the evolution of monogamy, and the incel movement. Using census data from 30 countries across Africa, Asia, and Oceania, as well as data from the historical United States, we find no clear evidence that polygyny is associated with higher proportions of unmarried men in society. Instead, high-polygyny populations often have marriage markets skewed in favor of men, and actually, men in high-polygyny populations usually marry more than men in low-polygyny ones. These findings challenge entrenched assumptions and inform debates on marriage systems, societal stability, and human rights.
Data, Materials, and Software Availability: The census microdata obtained from IPUMS International and IPUMS USA cannot be redistributed, but it can be downloaded at no cost after registering at https://www.ipums.org/ (45–47). To improve reproducibility, we have made the following materials available in an OSF repository (https://osf.io/tgb3k) (87): the UN model life tables used to produce the demographic model, the codebooks of the IPUMS extracts we use, and the R Markdown files used to analyze those extracts and produce the figures in the main text and supplement (https://www.pnas.org/doi/10.1073/pnas.2508091122#supplementary-materials).
URI: https://bura.brunel.ac.uk/handle/2438/33291
DOI: https://doi.org/10.1073/pnas.2508091122
ISSN: 0027-8424
Other Identifiers: ORCiD: Hampton Gaddy https://orcid.org/0000-0001-6397-4679
ORCiD: Rebecca Sear https://orcid.org/0000-0002-4315-0223
ORCiD: Laura Fortunato https://orcid.org/0000-0001-8546-9497
Appears in Collections:Department of Life Sciences Research Papers

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