Plenty of research has shown that scent is linked to sexual attraction, but the exact connection is a mystery. What fragrant chemical are men and women wooed by? Natural body odors play a role, but scientists have not been able to pin down exactly which of our personal fragrances entices a mate. A group of researchers from Switzerland has delivered the latest clue.
The team, based at the University of Bern, wanted to know if a protein called human leukocyte antigen, or HLA, is important to attraction-by-scent. HLA, which helps the immune system detect foreign invaders, also influences our personal scent and captures genetic differences between us.
The reason for focusing on HLA is to do with finding a mate that is different from us. A study from 2016 found that attraction and desire to mate was heightened between people whose cells, or genes, were different from their own. That makes sense: mating with someone genetically different from ourselves is advantageous in terms of survival. Because HLA encapsulates such genetic differences, it makes sense to ask whether the scents we find attractive are somehow tied to HLA.
Most research on HLA has focused on attraction in females. The Swiss researchers wanted to see if HLA influenced men.
To uncover exactly what scent attracts men, the researchers asked 42 women to collect body odor from under their armpits every night using pads of cotton. The women were told not to shower or share their bed with anyone before collecting their personal fragrance samples. The researchers also enrolled 94 men to sniff each pad, making sure to take in a neutral scent between, like a perfume shopper smelling coffee beans between fragrances. Participants ranked each sample on strength, attraction and likability. Blood samples of all males and females were tested so the researchers could catalog similarities and differences in HLA among the study recruits.
The results add to the mystery of attraction. The researchers found that the scents men found appealing were completely unrelated to HLA. The men were definitely attracted to certain body odors and not others, but their preferences showed no tie to HLA. Meaning? Maybe finding women who are genetically different isn't that important for men.
Psychologist and study co-author Janek Lobmaier believes the findings are more conclusive than prior research because the team accounted for women's menstrual cycles, which other studies have not. This matters because a woman's scent changes throughout ovulation, and there is some evidence that men prefer females at their most fertile.
"Because of the rigorous methodology, our study is probably the most conclusive to suggest that HLA plays an insignificant role in men’s preferences for women’s body odors," Lobmaier tells Newsweek via email.
Though the sample was small, James Roney, psychologist at the University of California Santa Barbara, who is not affiliated with the study, said the investigation was well executed. Because past research has presented alternative results, he believes a meta-analysis looking at the various studies would give a clearer picture of odor and attraction.
Until then, here is what we do know about what men want. “Men are clearly attracted by cues of youth, health, body shapes associated with health, etc.,” says Roney, “all of which supports attraction based on mating potential.”