The research, conducted by Natalia Jaguszewska, Grazyna Jasienska, and Urszula M. Marcinkowska of Jagiellonian University Medical College in Cracow, Poland, examined whether facial fluctuating asymmetry, the small, random deviations from perfect bilateral symmetry that arise from developmental imprecision, was related to multiple dimensions of female sexuality. The team measured not only long-term sociosexual orientation, including the number of sexual partners and openness to casual sex, but also current sexual activity and desire, captured through questions adapted from the Female Sexual Function Index. Seventy-five women aged between twenty and thirty-seven and a half years took part, most of them in relationships, and all were photographed three times across a single menstrual cycle under standardized conditions.

The technical rigor of the facial measurements is one of the study’s standout features. Researchers placed 124 anatomical landmarks on each photograph using PSYCHOMORPH software, with the person doing the delineation blind to the participants’ sexuality responses. The landmark configurations were then Procrustes-aligned using the R package geomorph, and asymmetry was computed as the Euclidean distance between the original and mirrored facial configurations, following established analytical methods. By averaging facial shape measurements across three separate photographic sessions, taken in the follicular phase, around mid-cycle, and in the late luteal phase, the team substantially reduced measurement error, a common weakness in asymmetry research.

At first glance, the raw correlations seemed to support the classic evolutionary prediction. Women with more asymmetrical faces reported fewer sexual partners in the past year, a statistical association of rho equal to minus 0.23. More asymmetrical women also scored lower on the attitude subscale of the revised Sociosexual Orientation Inventory, which measures views on casual, uncommitted sex, with rho equal to minus 0.25, and showed a weaker, borderline trend toward lower sexual desire, at rho equal to minus 0.21. On the surface, this looked like exactly the pattern the mate-selection framework would predict: symmetrical women, presumably signaling better biological condition, enjoying more open and active sexual lives.

But then the researchers did something that many previous studies in this field had not done adequately: they controlled for confounding variables. When place of residence, urban versus rural, and relationship status were added to the regression models, every single one of those associations vanished. The p-values for the asymmetry-sexuality relationships ranged from 0.42 to 0.91, nowhere near conventional significance thresholds. The apparent biological signal, it turned out, was almost certainly not a signal about faces and sexuality at all, but a statistical echo of where the women lived and whether they were partnered.

The confounding structure was substantial. Women from rural areas had significantly higher facial asymmetry than their urban counterparts, were less sexually active, reported lower sexual desire, and scored lower on most aspects of sociosexuality, including attitudes toward casual sex, numbers of one-night stands, and numbers of uncommitted partners. This pattern is consistent with earlier findings showing that people of lower socioeconomic status, who are disproportionately located in rural areas, tend to show higher fluctuating asymmetry, possibly reflecting poorer developmental conditions, more physically demanding labor, and greater exposure to stressors. Rural women in Poland also tend to be more conservative and religious, predominantly Catholic, which may contribute to lower reported sexual openness, and they were more often married or in a relationship, further shaping their sexual behavior.

The study’s authors are careful to note that place of residence should be treated as a contextual control variable rather than a confirmed causal mechanism. They did not have direct evidence linking specific environmental exposures, such as endocrine-disrupting chemicals, differences in physical workload, or farm environments, to facial asymmetry in their dataset. Still, the broader lesson is hard to escape: if a study had stopped at the simple correlations, it would have published a headline-grabbing claim that facially symmetrical women are more sexually open and active, a claim the fuller analysis could not support. The researchers explicitly raise the question of whether previously reported asymmetry-sexuality relationships in the literature would survive similar statistical controls.

The null result also lands in the middle of an ongoing debate about what facial symmetry actually tells us. While symmetrical faces have long been rated as more attractive in many studies, recent work has failed to find a correlation between symmetry and attractiveness, suggesting that other features, such as facial averageness or distinctiveness, may be better predictors of perceived beauty. Some researchers have even shown that preferences for symmetry depend on how a study is designed. A 2025 scoping review by Obrochta and colleagues highlighted the weak relationship between facial fluctuating asymmetry and health more generally, casting further doubt on the assumption that the face is a reliable billboard of biological quality.

From an evolutionary standpoint, the original hypothesis had a certain logic. Even though the number of sexual partners is not a reliable indicator of female reproductive success in the way it may be for men, women could in principle obtain indirect reproductive benefits from multiple partners, and if symmetry signals good genes, symmetrical women might be expected to secure more mates through intersexual selection. Earlier studies had linked body asymmetry to fewer lifetime partners and fewer extrapair copulations, and facial asymmetry to a later age at first reproduction. Yet the present data found no evidence for the first step of the proposed mate-value pathway: partnered women did not differ in facial asymmetry from single women, and asymmetry was unrelated to partner numbers even in the regression models.

The authors acknowledge the limitations of their sample, which was too small to support formal mediation analyses, and they call for larger, longitudinal studies that could disentangle whether variables like residence and relationship status function merely as statistical confounds or as part of genuine developmental pathways. They also suggest that future work should incorporate independent ratings of facial attractiveness to test whether attractiveness mediates any link between facial shape and sociosexuality. For now, the takeaway is a refreshing dose of scientific humility. The human face may still hold clues to our biology, but this study shows that some of the most tantalizing correlations in evolutionary psychology can evaporate the moment researchers account for the ordinary social geography of people’s lives. Culture, it seems, can masquerade convincingly as biology, and only careful, confounder-aware analysis can tell the difference.

Subject of Research: The relationship between facial fluctuating asymmetry and female sexuality, controlling for residence and relationship status

Article Title: Facial Asymmetry and Sexuality in Women

Article References: Jaguszewska, N., Jasienska, G., & Marcinkowska, U. M. (2026). Facial Asymmetry and Sexuality in Women. Archives of Sexual Behavior. https://doi.org/10.1007/s10508-026-03527-w

Image Credits: AI Generated

DOI: 10.1007/s10508-026-03527-w

Keywords: facial asymmetry, fluctuating asymmetry, sociosexuality, female sexuality, evolutionary psychology, facial attractiveness, mate selection, developmental stability, rural-urban differences, relationship status, Archives of Sexual Behavior, Poland