People often say the past matters in relationships—but new research suggests it may matter in surprisingly consistent ways. A large cross-cultural study published in Scientific Reports provides evidence that people tend to view potential long-term partners less favorably when they have had many previous sexual partners. This pattern held across 15 samples in 11 countries, and the researchers found little support for a sexual double standard: men and women evaluated extensive sexual histories similarly.
The study was led by Andrew G. Thomas of Swansea University, alongside an international team of collaborators from institutions across Europe, Asia, Australia, and the Americas. Their aim was to explore the way sexual history—including the number of sexual partners and the timing of those encounters—influences perceptions of someone’s desirability as a long-term partner.
“There are a couple of things that inspired me to pursue this line of research,” Thomas told PsyPost. “First and foremost, discussion of sexual history (‘body count’) online is quite rampant and often quite toxic. It’s oversimplified, riddled with double standards, and lacks nuance. I think this type of research is interesting because it can help answer some key questions around a subject area that people clearly care about, but in a balanced and thoughtful way.
“The second reason is that I wanted to build on our previous work from 2016, which just focused on number of past partners. That study found some really interesting evidence of a lack of sexual double standards and also that people prefer a mate with a bit of a past, but not too much.”
“Two things stuck with me from that earlier research. The first was the idea that people use ‘the number’ in different ways, and that there are contextual factors that can influence how it’s appraised. For example, if someone has had four sexual partners in the last six months, most people would evaluate that very differently to someone who’s had four partners over the last 10 years.”
“The second point was that our original study was only conducted in the United Kingdom. We wanted to know whether what we found was a specifically British phenomenon or something more universal. So, as with much of my work, I was interested in doing a cross-cultural follow-up.”
The researchers conducted three studies involving a total of 5,331 participants. The first study recruited heterosexual adults in the UK via social media. The second expanded to include British and Greek participants of all sexual orientations. The third was the most ambitious, bringing in over 4,500 participants from 11 countries across five global regions. These included China, Australia, Norway, the Czech Republic, Brazil, Slovakia, Italy, Poland, and the United States, among others.
In each study, participants were shown visual representations of fictional suitors’ sexual histories. These images depicted a series of vertical lines, each representing a sexual partner, spaced across a timeline from sexual debut to six months before the present. Some timelines showed an increase in sexual activity over time, others a decrease, and some a steady pattern. Participants were asked how willing they would be to pursue a long-term relationship with the individual represented by each timeline. Three total partner numbers were shown: four, twelve, and thirty-six.
Participants also completed a measure of sociosexuality, which assesses openness to uncommitted sexual relationships. This allowed the researchers to explore whether people’s mating strategies influenced their judgments of others’ sexual histories.
Across all three studies, a consistent pattern emerged: people preferred partners with fewer past sexual partners. Willingness to pursue a long-term relationship declined significantly as partner numbers increased from four to twelve, and again from twelve to thirty-six. This effect was strong across cultures, with only minor differences in effect size. For example, in China, men showed slightly more tolerance than women for partners with higher numbers of past sexual partners, but this was not a widespread trend. Men and women both showed this pattern, and sex differences were minimal and inconsistent.
Beyond the sheer number of partners, the timing of those encounters played a significant role. Participants expressed more willingness to date someone whose sexual activity had slowed down over time compared to someone whose activity had increased or remained steady. This effect was especially pronounced when the total number of past partners was high. When someone had many past partners but most of those encounters were in the more distant past, they were judged more favorably than someone whose encounters were more recent.
“The most important takeaway from our findings is that, almost universally, people do pay attention to the past sexual history of their prospective partners,” Thomas explained. “Generally speaking, that tracks risk. People with a large number of past partners may have a greater interest in casual sex, may be less interested in settling down, might be at higher risk of sexually transmitted diseases etc. We found that pattern in nearly every culture, and it may well reflect part of our evolved mating psychology for balancing risk when selecting mates. That’s the first big finding: cross-cultural consistency. The second is that timing matters. The number of past partners is evaluated more favorably if someone shows a pattern of slowing down and having fewer new partners over time.”
“Those time effects don’t eliminate the influence of past partner number, but they do soften it. That’s good news for someone who may feel nervous about having an adventurous past, because time and a clear commitment to long-term relationships can counteract some of the bias against a large number of past partners. Another important takeaway is that we found virtually no evidence of a sexual double standard.”
“People judged men and women in the same way, and we found that across countries and cultures,” Thomas said. “Time and again, when we ask participants what society at large thinks, people expect a sexual double standard—men’s histories overlooked while women are judged more harshly. But when we ask individuals to make their own judgments, and when we look at what people actually do, we find no evidence of such a standard. That’s a really interesting distinction.”
Sociosexuality also moderated the results. People who scored higher in sociosexuality tended to judge suitors with many partners more leniently. However, even these participants preferred patterns showing a decrease in sexual activity over time. This suggests that while some individuals are more permissive overall, the broader patterns still influence their judgments.
“One of the findings that challenged my expectations came from including a measure of sociosexuality (people’s interest in short-term mating),” Thomas remarked. “I expected that those high in sociosexuality would show a reversed pattern, reasoning that if someone is very interested in casual sex, then a partner with many recent partners might signal openness to casual sex with them. But that wasn’t the case. We found the same effects: a higher number of past partners, especially recent ones, led to less favorable evaluations. The only difference was that for individuals high in sociosexuality, the negative effects were somewhat muted, though not reversed.”
But the study, like all research, has some caveats. While the study had a large and culturally diverse sample, it did not use nationally representative populations. Most participants were young adults and were recruited online. The visual format of the sexual history task, while offering control and clarity, does not fully replicate how sexual history is shared in real-world interactions, where information is often conveyed through stories, social media, or reputation.
Another limitation is that the study focused solely on long-term relationship desirability. Future research could explore whether these effects differ in short-term contexts, where risk perceptions may be different, and sex differences may be more pronounced. The authors also suggest investigating how sexual history interacts with other traits such as physical attractiveness, intelligence, or kindness, which are often weighed together in real-world mate choice.
“We did a good job gathering cross-cultural samples, but they could have been more standardized and more representative within each country,” Thomas told PsyPost. “There’s also scope to include more rural samples. Looking forward, an important next step is to investigate how sexual history information is integrated with other valued traits like humor, physical attractiveness, kindness, intelligence, and so on. Another is to expand beyond just number and timing, to consider aspects such as the type of partners someone has had or the intentions behind those relationships. People’s sexual histories are rich, and there are many potential angles to explore.
“In terms of long-term goals, I’d like to see sexual history placed more firmly on the map of mate-preference research. We’ve shown that it’s important and almost universally considered, but most mate-preference studies don’t look deeply into sexual history. They focus on things like attractiveness or intelligence, and sometimes include chastity, but that’s only part of the story. In modern Western societies, most people aren’t chaste, and there’s far more nuance to sexual history that could be integrated into wider mate-preference work. I’d also like this research to help counter some of the toxic “manosphere” narratives around concepts like ‘body count.’ Those narratives often rely on presumed sexual double standards, but our findings point strongly to the contrary.”
The study, “Sexual partner number and distribution over time affect long-term partner evaluation: evidence from 11 countries across 5 continents,” was authored by Andrew G. Thomas, William Costello, Mons Bendixen, Leif Edward Ottesen Kennair, Menelaos Apostolou, Klára Bártová, Ondřej Burýšek, Rob Lowe, Peter Jonason, Marta Kowal, Yago Luksevicius de Moraes, O. Jiaqing, Piotr Sorokowski, Danielle Sulikowski, Zuzana Štěrbová, Jaroslava Varella Valentova, Marco Antonio Correa Varella, Yan Wang, Arnaud Wisman, Paula Wright, and Steve Stewart-Williams.
