A new study published in The Journal of Sexual Medicine provides new insights into female sexual attraction, revealing a striking discrepancy between implicit and explicit measures of gynephilia—the sexual preference for women. Scientists discovered that while only a small percentage of participants explicitly identified as non-heterosexual, implicit measures found that a majority of women exhibited gynephilic attraction. These findings suggest that many women experience attraction to other women without necessarily engaging in or desiring sexual encounters.
“I have been deeply interested in the Darwinian paradox of homosexuality for over 25 years,” said study author Andrea S. Camperio Ciani, a full professor of evolutionary psychology, behavioral genetics and neuroscience at the University of Padova.
The Darwinian paradox of homosexuality stems from a central question in evolutionary biology: if reproductive success drives natural selection, how can traits that seemingly reduce reproductive output—such as exclusive same-sex attraction—persist across generations? Individuals who do not engage in heterosexual relationships, or have fewer offspring due to their orientation, would theoretically pass on fewer genes, leading to the eventual decline of such traits in the population.
Yet, homosexuality remains a stable and enduring aspect of human variation, observed consistently across cultures and even in other species. This apparent contradiction suggests that there must be factors at play that allow these traits to persist within an evolutionary framework.
“Through my research, I uncovered evidence of a partial genetic influence on homosexuality, maintained through a mechanism of sexually antagonistic selection, solving the long-lasting Darwinian paradox of the genetic transmission of homosexuality,” Camperio-Ciani said. “This mechanism promotes male homosexuality in some male individuals, while significantly enhancing fecundity in their maternal female relatives.”
This phenomenon, known as sexually antagonistic selection, suggests that genes associated with same-sex attraction in one sex may confer reproductive benefits to the opposite sex. In practical terms, genetic predispositions linked to homosexuality can enhance the fertility of relatives, thereby increasing the overall reproductive success of the family. This type of kin selection allows these genes to persist despite their apparent disadvantage for individual reproductive output.
“In the case of female homosexuality, this selection appears to increase fecundity across the entire familial pedigree,” Camperio-Ciani explained. “Based on these findings, I hypothesized that androphilia—the sexual preference and arousal to male images rather than female images—could serve as a necessary, but not sufficient, genetic prerequisite for male homosexuality. A recent study by our team strikingly confirmed this hypothesis. Building on these results, we turned our focus to gynephilia in females to explore whether a similar mechanism might act as a genetic prerequisite for non-heterosexuality in women.”
By distinguishing between implicit (unconscious) and explicit (self-reported) measures of attraction, the researchers aimed to shed light on whether same-sex attraction in women reflects biological predispositions, social constructs, or an interplay of both.
Participants were recruited globally through an online platform, ensuring a diverse sample of 555 women aged 18 to 65 years. To mitigate biases and confirm data accuracy, data from individuals whose responses were inconsistent or unreliable were excluded, leaving a final sample of 491 participants.
The methodology included three primary tasks. First, participants completed a short biographical questionnaire to gather demographic data such as age, education, and geographic location. Second, they performed two Implicit Association Tests (IATs): the Autobiographical IAT (A-IAT) and the Sexual Preference IAT (SP-IAT). The A-IAT was used to verify participants’ gender by measuring the speed and accuracy of their responses to gender-related statements. The SP-IAT assessed implicit sexual preferences by examining participants’ automatic associations between male and female traits and concepts of sexual attractiveness or repulsiveness.
Finally, participants explicitly reported their sexual orientation using the Kinsey Scale, which measures self-identified sexual preferences on a continuum from exclusively heterosexual to exclusively homosexual.
The researchers found a significant discrepancy between implicit and explicit measures of sexual orientation. On the explicit Kinsey Scale, the majority of participants (80.4%) identified as heterosexual, while 14.9% identified as bisexual and 4.7% as homosexual.
However, the SP-IAT indicated that 67.8% of participants exhibited implicit gynephilic preferences, with only 5.9% showing implicit androphilic preferences (attraction to men over women). Notably, implicit gynephilia was observed even among participants who explicitly identified as heterosexual, suggesting that implicit measures may capture aspects of sexual preference that are not reflected in self-reported data.
“Our findings were surprising, as they revealed a much higher prevalence of implicit gynephilia than explicitly reported non-heterosexuality, suggesting complex dynamics that differ significantly from those observed in males,” Camperio-Ciani told PsyPost. “This suggests that many women may harbor same-sex preferences that are not consciously acknowledged or socially expressed.”
Follow-up analyses explored whether implicit gynephilia might reflect an appreciation of female aesthetic beauty rather than sexual attraction. When asked to rate images of men and women on aesthetic attractiveness and potential as sexual partners, participants rated women higher for aesthetic appeal but men higher as potential sexual partners. This pattern suggests that implicit measures of gynephilia may capture broader dimensions of attraction beyond sexual interest.
“We were very surprised to discover that the rate of gynephilia in females was remarkably high worldwide,” Camperio-Ciani explained. “Upon further analysis, we hypothesized that this might be due to the overlap between aesthetic beauty and erotic beauty in females, leading to a greater prevalence of gynephilic responses.”
“In contrast, for males, gynephilia is predominantly associated with heterosexual attraction, while androphilia is relatively rare—observed in only about 18% of males, compared to almost 75% gynephilia in females. This suggests that, in humans, gynephilia may be the norm, but unlike androphilia in males, it does not reliably predict homosexuality in females. Instead, it reflects a broader appreciation for female beauty that may not necessarily translate into sexual orientation or behavior.”
Despite its strengths, the study has limitations. While the sample was geographically diverse, it skewed toward young, highly educated participants, limiting generalizability. The study’s reliance on implicit association tests, which have faced criticism, also warrants caution.
“One major caveat of our study is the reliance on implicit measures like the Implicit Association Test, which, while innovative and insightful, has faced scrutiny regarding its validity in recent years,” Camperio-Ciani said.
The researchers suggest several avenues for future exploration. For instance, they propose examining the biological and cultural factors that influence the disconnect between implicit preferences and explicit orientations. Further studies could investigate how implicit measures evolve over time or vary across different life stages. Additionally, exploring how implicit gynephilia relates to actual sexual behaviors could deepen understanding of the complex interplay between attraction, identity, and social context.
“My long-term goals for this line of research are to deepen our understanding of the biological, genetic, and social mechanisms underlying sexual orientation and preferences,” Camperio-Ciani explained. “I aim to explore how implicit sexual preferences interact with cultural and environmental factors to shape explicit orientations and behaviors. Additionally, I hope to refine the tools we use to study these phenomena, addressing limitations such as the validity of implicit measures and broadening cross-cultural representation. Ultimately, my objective is to contribute to a more nuanced view of human sexuality, challenging stereotypes and fostering greater acceptance through scientific insight.”
Camperio-Ciani noted that research on homosexuality can have profound real-world implications, fostering greater understanding, acceptance, and inclusion of sexual diversity. For example, evidence of genetic and biological influences on homosexuality has been cited in legal decisions, such as the decriminalization of homosexuality in India, demonstrating how scientific findings can directly support social justice and legislative change.
“I am particularly proud of the real-world impact of my earlier work on the genetic influences of homosexuality, which was cited in the landmark 2018 decision by the Supreme Court of India to decriminalize homosexuality due to its partial genetic bases that could not be discriminated,” he said. “This ruling overturned a law that previously sentenced individuals to up to 10 years of hard reclusion in Indian prisons, granting new freedom, inclusion, and civil rights to an estimated 60 to 100 million homosexual individuals in the Indian subcontinent.”
“These are the kinds of outcomes that I find deeply meaningful, as they demonstrate how scientific research can contribute to tangible social progress and equality. I hope that my ongoing work continues to inspire similar changes, fostering greater understanding and acceptance of diversity in human sexuality.”
The study, “Worldwide study reveals fluid sexual preferences in females and no association between gynephilia and non-heterosexuality,” was authored by Andrea S. Camperio Ciani and Daiana Colledani.
