Men with high testosterone are more likely to cheat on their partners, new research has suggested.
Meanwhile in women, the hormone has been linked with solo sex, or lesbian flings.
While there are many theories about why men and women cheat, new research has shed some light on the role that increased levels of testosterone in men could play in that particular sexual behaviour.
The study, published in The Journal of Sex Research, analysed data from the third British National Survey of Sexual Attitudes and Lifestyles and set out to provide detailed insight into how the hormone has a different affect on the sexual behaviour of men and women.
The researchers, from London School of Hygiene and Tropical Medicine (LSHTM), UCL, University of Manchester, and the National Centre for Social Research (NatCen), measured testosterone in saliva samples from nearly 4,000 adults and used questionnaires to investigate links between androgen quantity and how people express their sexuality.
Findings revealed that men with higher levels were likelier to have had more than one lover at the same time in the last five years - and to have had recent sex.
In women, testosterone was significantly higher in those who had experienced a same sex relationship.
They also reported masturbation more recently and frequently.
Until now the hormone has commonly been regarded as the biological driver of sexual desire in men, although evidence is inconclusive.
Its role in female desire is even less understood.
Commenting on the findings lead author Wendy Macdowall, of the London School of Hygiene and Tropical Medicine, said: "There's a sparsity of population level data on the differences between men and women in the relationship between testosterone and sexual function, attitudes and behaviour.
"Questions have been raised about the nature of sexual desire in women and how little we understand about what it is that is desired.
"Our data tends to confirm that differences between men and women need to be understood by examining them in the context of social as well as hormonal influences on sexual function and behaviour.
"Testosterone's marked link with masturbation among women, in the absence of an observed link with aspects of heterosexual partnered sex, may be seen as consistent with the notion of a stronger moderating effect of social factors on hormonal influences on women’s behaviour."
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Past research on hormones and female sexuality has tended to focus solely on aspects of reproduction such as menstruation.
In men, the focus has been on their role in the ability to perform sexually such as to achieve an erection.
Saliva samples from 3,722 participants aged 18 to 74 - 1,599 men and 2,123 women - were scanned using a state of the art technique.
Those who had at least one sexual partner in the year prior to interview were asked about problems with sexual function, such as lacking interest in having sex and having trouble getting or keeping an erection.
A range of behaviours were measured including different practices in the previous four weeks including frequency of masturbation and the number and type of partners over the past five years and lifetime.
Participants were also asked their views about different types of sexual relations such as one-night stands.
Overall, there was a stronger link for women than for men between higher testosterone levels and solitary sexual activity as opposed to with a partner.
The researchers said this could be related to the "different meanings and motivations women attach to solitary and partnered sex."
Testosterone, the male sex hormone is mostly made in the testicles, but also in adrenal glands, which are near the kidneys.
It causes the voice to deepen, body hair to grow and the genitals to become larger during puberty.
Women also create small amounts of testosterone in the ovaries and adrenal glands. It affects their fertility and bones and muscles.
Low testosterone in men can cause erection problems, low sex drive, infertility, weakened muscles and bones, body fat gain and hair loss.
Too much testosterone, however, can trigger puberty in boys under the age of nine, is linked to aggression, and can increase the risk of prostate problems, including cancer.
Higher levels in men have previously been linked with risk-taking behaviour - as well as increased attraction to the opposite sex.
Men with high levels have also been found to be perceived as more attractive by women.
Earlier this year it was predicted there would be an "explosion" of cheating following the easing of coronavirus restrictions and once large swathes of the UK population have been vaccinated.
The findings from Illicit Encounters, which asked 2,000 users how their dating lives will change as the pandemic eases, showed 74% were planning to start sleeping around within months.
They believe that the country's vaccination figures was giving would-be cheaters peace of mind when it came to embarking on an affair.
Indeed, the survey discovered 86% of users felt "more relaxed" about having extra-marital liaisons, knowing that many will soon have a layer of protection from the virus.
Last month the affairs website predicted the increasing numbers of employees returning to office desks could lead to a "surge" in workplace romances.
And not just for singletons, researchers said there would be a rise in cheating as employees have the first proper opportunity to stray in over a year.
While the site said there was always a rise in post-summer affairs, this autumn is likely to see an even more pronounced effect.
Recent research also has shed some light on what’s going on in the brain of a usually honest person, which may cause them to cheat.
While it is generally assumed that the amount of “willpower” a person has can impact their decision to do something dishonest, research, from Rotterdam School of Management, Erasmus University (RSM), has revealed that willpower, (aka “cognitive control” in psychology speak), does not serve the same purpose for everyone.
In fact, the results, published in Proceedings of the National Academy of Sciences (PNAS), revealed that cognitive control actually enables cheating for people who are typically honest, while at the same time facilitating honest decisions for serial cheaters.
The findings come following further research released last year which suggests there is a gender disparity between how men and women view different types of betrayal.
The research, published in the Journal of Relationships Research, looked into the different types of infidelity and the factors behind forgiveness.
While men usually regard physical infidelity, when the partner has sex with another person, more seriously, for women, emotional infidelity, when the partner initiates a close relationship with another person, is viewed as more serious.
Additional reporting SWNS.