Your genetics impacts both how you smell and how you perceive odors. It can even influence romantic and sexual attraction.

Body odor actually impacts everyone differently. Some people can work up a sweat without emitting a scent, while others have trouble avoiding B.O. regardless of activity level.

So, what gives? Why do some people produce a pungent body odor and others don’t? And why do some people believe that we can determine genetic compatibility through smell?

Let’s look at what we know and what we’re still learning about the genetics of how you smell.

Let’s start by stating that smell can occur anywhere on your body, but much of the research focusing on human body odor tends to center the conversation on armpits and underarm odor.

Research suggests that yes, genetics can influence whether you’re one of the many whose sweat contains compounds that bacteria eat, leading to armpit odor.

However, genetics can also determine how you interpret smells, including body odor.

A 2007 joint study between researchers at Duke University Medical Center and Rockefeller University followed 400 volunteers who were asked to sniff 66 different scents that represented various distinct odorant (smell) molecules. These scents ranged from more everyday smells like cinnamon and spearmint to sweat-derived steroids including androstenone and androstadienone.

The study specifically looked at how the human odor receptor, the OR7D4 gene, responds to exposure to specific to the steroids mentioned above. After sniffing and rating the various scents, the respondents submitted blood samples so that the researchers could look for OR7D4. They found that:

  • Participants with two copies of the most common version of OR7D4 found androstadienone most offensive.
  • Those with just one or with two copies of a similar version of the gene thought that the steroid smelled sweet.
  • Those who had the rarest version of OR7D4 struggled to detect either of the two steroids during the sniff test.

Just as our ability to perceive body odor seems to be controlled by genetics, so too is whether or not we emit the chemical that leads to smelly sweaty odors. In particular, research points to the ABCC11 gene as directly responsible for underarm odor.

Oddly enough, this gene also determines whether people produce wet or dry earwax. Interestingly, those who tend to produce dry earwax also lack the necessary chemical needed to feed the bacteria that cause underarm odor.

This means that those people don’t have to worry about underarm odor and also wouldn’t benefit from wearing deodorant. According to a 2013 study published in the Journal of Investigative Dermatology, roughly 2% of Europeans and most East Asians lack the ABCC11 gene.

With all this talk about body odor and whether someone’s sweat smells good or bad, it’s understandable that the next logical question is: Can you use smell to determine genetic compatibility?

Evidence suggests that while people might not purposely seek out partners with specific scents, body odor does play a subliminal role in our partner selection.

Some theories suggest that this might be an evolutionary adaptation to actively avoid inbreeding. Others propose that this is an evolutionary attempt to ensure that any future offspring have robust immune system that can effectively ward off a larger range of pathogens.

Theories around scent compatibility

A 2003 study that was published in Behavioral Ecology looked to further review prevailing theories that centered on the ideas of scent dissimilarity. The “scent dissimilarity” theory proposes that women prefer the scent of a man whose major histocompatibility complex (MHC) genotype is most dissimilar to their own.

Previous research has shown that in both women on contraceptives and those not on contraceptives, a preference toward men with dissimilar MHC genotypes holds true. (The MHC complex is involved in your immune system.)

However, another caveat exists. This same 2003 study also found that scent-based preferences can vary depending on when a woman is exposed to scents during her menstrual cycle. Research suggests that during the time surrounding the ovulation window (when fertility is highest), olfactory sensitivity is also at its highest for detecting androstenone.

A 2012 study focused on men’s ability to determine whether a woman’s body scent was pleasant or not. Women provided samples during low- and high-fertility days. These samples were later smelled by male respondents who nearly overwhelmingly chose the high-fertility samples as more attractive and were able to easily identify the high-fertility samples from the low-fertility ones.

In short, men can subconsciously perceive when ovulation is occurring through body odor, and it’s possible that this can influence attractiveness and sexual approach behavior.

Attraction and scent in the LGBTQ+ community

Studies quoted in the previous section don’t make a delineation between sex and gender, but we’d like to.

Sex is determined by chromosomes, and gender is a social construct that can vary between time periods and cultures. Both of these aspects are acknowledged to exist on a spectrum both historically and by modern scientific consensus.

At the time of publication, no studies on queer attraction involving scent could be found. It’s possible that LGBTQ+ people may react in similar ways, seeking out the same scent compounds in romantic or sexual partners, but we don’t know. If you’d like to get involved with ongoing research on the subject, you can see what’s available at ClinicalTrials.gov.

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Current research has shown that humans are influenced by their partner’s scent when determining attractiveness and compatibility. Personal hygiene plays a big role in your personal scent, but so do your genetics. Those with the ABCC11 gene (which controls underarm odor and ear wax) produce chemicals that scent-producing bacteria can feed on.

Learning that body odor — or the lack of it — is genetically influenced and can also tip the scales during partner selection is an intriguing thought. But it’s important to keep in mind that people don’t solely rely on scent when choosing a partner. Having an interesting personality and being a good partner still comes into play.