A new study co-authored by SFI External Professor Laura Fortunato (University of Oxford) challenges a long-standing claim that polygynous marriage, where men have multiple wives, creates a surplus of men with no prospect of ever marrying. A large contingent of unmarried men is widely believed to lead to negative social outcomes, including interpersonal violence and, in extreme cases, civil conflict.
The research was published in PNAS in October with co-authors Hampton Gaddy at the London School of Economics and Rebecca Sear at Brunel University London. Combining demographic modeling and recent census data from 30 countries across Africa, Asia, and Oceania, as well as U.S. census data from 1880, the team found that polygyny often coexists with high rates of marriage among men. This pattern contradicts the idea that polygyny leaves large numbers of men without wives.
For example, across over 84 million individual records in the 30-country sample, the researchers found a negative association between the prevalence of polygyny and that of unmarried men at the sub-national level in nearly half of the censuses, and a positive association in less than 10%. The researchers posit that, where polygyny is allowed, cultural norms promoting marriage are likely to offset demographic and other constraints that may otherwise limit men's opportunities to marry.
Adapted from a University of Oxford Press release (November 17, 2025)
Read the paper "High rates of polygyny do not lock large proportions of men out of the marriage market" in PNAS (August 27, 2025). DOI: 10.1073/pnas.250809122