Study links adult sexlessness to genetics, social factors, and lifestyle in large international sample

A large-scale analysis published in the Proceedings of the National Academy of Sciences examined data from more than 400,000 adults, including about 13,500 Australians and 405,117 residents of the United Kingdom. The study identified 3,929 participants who reported never having vaginal, oral, or anal intercourse. Researchers emphasized that the data reflect whether someone has ever had sex, not whether they desire sex, and noted that sexlessness likely reflects a mix of voluntary and involuntary factors.

Genetic factors accounted for roughly 15 percent of the variation in sexlessness, with the remainder explained by environmental and social influences. The researchers described distinct patterns by sex. Among men, factors such as grip strength, body size, income, snoring, mobile-phone habits, life satisfaction, and having someone to confide in were more strongly associated with never having sex. Among women, work-related aspects like hours worked showed stronger links to lack of sexual activity when considered alongside other variables, while income and the presence of close, confiding relationships were more significant predictors for men. Across both sexes, individuals reporting no sexual experience tended to be highly educated, introverted, and, intriguingly, scored higher on cognitive ability than their peers who had had sex.

“Wearing glasses at an early age, and other stereotypically ‘nerdy’ features, may affect adolescent dating experiences,” said Dr. Brendan Zietsch, Associate Professor at The University of Queensland and the study’s lead author. “This, in turn, may affect one’s romantic confidence into adulthood.” He added that such traits could influence social opportunities and, ultimately, romantic prospects. He also noted that the study found a correlation between sexlessness and certain mental health traits, including a higher prevalence of autism spectrum disorder and anorexia, while depression, anxiety, and ADHD were less common among those who had never had sex. He stressed that the findings likely reflect a mixture of voluntary and involuntary sexlessness and do not identify a single cause.

The study highlights a complex set of interactions between genetics and environment. A genetic correlation indicates that genes associated with one trait can also be linked to another, and the researchers described an array of links between sexlessness and other characteristics. While genetics accounted for a portion of the pattern, researchers emphasized that environmental context—regional demographics, socioeconomic conditions, and personal circumstances—shaped sexual activity in meaningful ways. The authors caution that more work is needed to determine causality and to understand whether sexlessness reduces happiness or loneliness or simply reflects a social reality in which some individuals have fewer opportunities to form sexual relationships.

Participants without sexual experience also exhibited behavioral patterns consistent with social isolation. The data showed less time spent on mobile phones, fewer visits to friends and family, and fewer opportunities to socialize or form close relationships. These patterns align with social isolation, which can hinder the chances of meeting potential partners. The study also found regional and socioeconomic differences that influenced sexual activity, particularly among men: in areas with fewer women and greater income inequality, men were more likely to remain sexless, suggesting that local social environments shape romantic opportunities.

The researchers emphasize the interaction between inherited genetic factors and social realities. Zietsch described the concept of genetic correlation, explaining that the genes linked to one trait can be associated with other traits as well. “In this way, we found an array of interesting links between sexlessness and other traits,” he said. The overall picture suggests that sexlessness in adulthood arises from a blend of biology and life circumstances rather than a single, isolated cause.

One of the study’s central uncertainties is whether sexlessness reflects a voluntary choice or an involuntary outcome. The researchers only collected data on whether individuals had ever had sex, not whether they desired sex. “Many sexless individuals in the sample may be asexual,” Zietsch acknowledged, underscoring that the findings likely reflect a mix of voluntary and involuntary factors. The research also raises questions about how a lack of sexual experience might influence well-being, loneliness, and social connectedness, suggesting a potential feedback loop between social isolation, emotional state, and sexual activity. While the findings illuminate a broad spectrum of factors, they do not offer a simple explanation or a single causal path.

The study’s authors stress that the results should be interpreted cautiously and within the broader context of human sexuality. They call for further research to unpack the relative weights of genetic versus environmental influences and to explore how changes in social settings and life circumstances might alter sexual activity over time.

The report contributes to a broader conversation about how genetics, mental health, education, and social life intersect with sexual behavior. It adds nuance to the understanding of sexlessness as a phenomenon that touches biology, psychology, and societal structure, rather than a single, easily explained trait. As researchers continue to explore these connections, the findings offer a cautious reminder of the complexity behind human sexuality and the many factors that shape intimate life.

In sum, the study presents a multifaceted picture: sexlessness in adulthood appears to arise from a combination of inherited traits and life circumstances, with regional and socioeconomic context shaping opportunities as much as biology. The work underscores the importance of considering a wide range of influences when examining sexual behavior and well-being, and it highlights the need for ongoing inquiry into how personal, genetic, and environmental factors interact over the life course.