We’re told all our lives to find attractive, healthy mates. In doing so, our children will then be more likely to survive, as they will have inherited good genes. Although that’s the short version of it, new research gives credence to it, finding that fitter, slimmer men hold fewer concentrations of “potentially pathogenic species of bacteria” in their noses.

Obviously, the nose is a major gateway for pathogens to enter the body — mucus usually catches them before they go further. And although the flu and the common cold may be the first kinds of bacteria to come to mind, other more harmful pathogens also get trapped, including bacterial meningitis and antibiotic-resistant staph.

“According to an evolutionary point of view, traits related to attractiveness are supposed to be honest signals of biological quality,” said Dr. Boguslaw Pawlowski, the study’s leader from the University of Wroclaw in Poland, according to CTV News. “We analyzed whether nasal and throat colonization with potentially pathogenic bacteria is related to body height and BMI (body mass index) in both sexes.”

For the study, Pawlowski and colleagues gathered mucus samples from the throats and noses of 90 men and 103 women, all of whom were considered healthy. The researchers looked at the mens BMIs — measures of body fat based on height and weight — and the women’s waist-to-hip ratio. They also tested the samples for concentration levels of six different types of bacteria, including colonies of Staphylococcus and Streptococcus. The most common pathogen they found was Staphylococcus aureus, which causes a range of illnesses from skin infections to food poisoning.

Interestingly, there was no association between women and high or low levels of the pathogens. Among the men, those with “relatively high lean body mass in comparison to fat content appeared less likely to be colonized by opportunistic and therefore potentially [harmful] microorganisms,” the researchers wrote, according to HealthDay.

The reason more attractive men could be less prone to bacterial colonization could lie in their higher levels of testosterone, the researchers said. A 2012 study published in the journal Nature Communications found that men who had stronger immune system responses were also more attractive and less stressed, according to Time Magazine.

Source: Pawlowski B, Nowak J, Borkowska B, et al. Human body morphology, prevalence of nasopharyngeal potential bacterial pathogens, and immunocompetence handicap principal. American Journal of Human Biology. 2014.