Life without sex: Large-scale study links sexlessness to physical, cognitive, and personality traits, socioecological factors, and DNA
Romantic (typically sexual) relationships are important to personal, physical, mental, social, and economic well-being, and to human evolution. Yet little is known about factors contributing to long-term lack of intimate relationships. We investigated phenotypic and genetic correlates of never having had sex in ~400,000 UK residents aged 39 to 73 and ~13,500 Australian residents aged 18 to 89. The strongest associations revealed that sexless individuals were more educated, less likely to use alcohol and smoke, more nervous, lonelier, and unhappier. Sexlessness was more strongly associated with physical characteristics (e.g., upper body strength) in men than in women. Sexless men tended to live in regions with fewer women, and sexlessness was more prevalent in regions with more income inequality. Common genetic variants explained 17% (SE = 4%) and 14% (SE = 3%) of variation in sexlessness in men and women, with a genetic correlation between sexes of 0.56 (SE = 0.17). Polygenic scores predicted a range of related outcomes in the Australian dataset. Our findings uncover multifaceted correlates of human intimacy and raise important lines of enquiry in the evolutionary and social sciences.
Authors
- Dirk J. A. Smit (ORCID: https://orcid.org/0000-0001-8301-8860)
- Fredrik Ullén
- Nicholas G. Martin (ORCID: https://orcid.org/0000-0003-4069-8020)
- Abdel Abdellaoui (ORCID: https://orcid.org/0000-0003-1088-6784)
- Renáta Androvičová (ORCID: https://orcid.org/0000-0002-1099-0891)
- Miriam Anna Mosing (ORCID: https://orcid.org/0000-0003-2049-125X)
- Laura W. Wesseldijk (ORCID: https://orcid.org/0000-0002-9900-0371)
- Joëlle A. Pasman (ORCID: https://orcid.org/0000-0001-7558-0482)
- Scott D. Gordon (ORCID: https://orcid.org/0000-0001-7623-328X)
- Karin J. H. Verweij (ORCID: https://orcid.org/0000-0001-9868-7821)
- Brendan P. Zietsch (ORCID: https://orcid.org/0000-0003-0274-6140)
Institutions
- The University of Queensland (AU)
- The University of Melbourne (AU)
- QIMR Berghofer Medical Research Institute (AU)
- Karolinska Institutet (SE)
- Max Planck Institute for Empirical Aesthetics (DE)
- Amsterdam University Medical Centers (NL)
- Melbourne Health (AU)
- National Institute of Mental Health (CZ)
- University of Amsterdam (NL)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2025-09-16
- DOI
- https://doi.org/10.1073/pnas.2418257122
- Citations
- 4
- Primary Topic
- Genetic Associations and Epidemiology
- Type
- article
- Field-Weighted Citation Impact
- 7.27
Funders
- QIMR Berghofer Medical Research Institute
- Stichting Volksbond Rotterdam
- Amsterdam University Medical Centers
- Universiteit van Amsterdam
- Karolinska Institutet
- Max-Planck-Gesellschaft
- Agentura Pro Zdravotnický Výzkum České Republiky
- Melbourne School of Psychological Sciences
- National Institute of Mental Health