Humans Can Smell Gender: Depends on Sexual Orientation and Biological Sex

Humans can detect someone's gender based on their sense of smell alone, according to researchers who reported their findings in journal Current Biology. And whether or not we realize it, humans identify someone as masculine or feminine based on their sexual preference and biological sex.

To reach this conclusion, lead researcher Wen Zhou and her colleagues exposed participants to female, male or neutral scents without them being able to distinguish one from the other. They took a whiff of the male hormone androstadienone and the female hormone estratetraenol, both active steroid ingredients.

Earlier studies showed that androstadienone, found in male semen and armpits, can promote positive mood in females as opposed to males. Estratetraenol, first identified in female urine, has similar effects on males, the authors describe in a statement.

While being exposed to a smell, the participants were then asked to watch a video of a series of dots that outlined a figure walking, called point-light walkers (PLWs). The participants then had to determine whether the walking dots had a more masculine or feminine gait.

When straight males were exposed to the female smell, they consistently identified the gait of the dots as feminine. Likewise, when straight females and homosexual men were exposed to the male smell, they consistently identified the PLWs as masculine in nature.

Interestingly, bisexual participants and homosexual women were not nearly as predicable, and their answers varied regardless of what odor they smelled.

"Our findings argue for the existence of human sex pheromones," Zhou of the Chinese Academy of Sciences said. "They show that the nose can sniff out gender from body secretions even when we don't think we smell anything on the conscious level.

This study suggests that in this respect, humans are quite animalistic in nature. Most mammals use their sense of smell to distinguish gender, according to MDConnects, although rodents may have a difficult time of it, a related study indicates.