Intrasexual differences in olfaction – influence of sexual orientation and gender nonconformity

As mentioned above, gender is the (second) most important demographic factor influencing olfactory capabilities. However, the same mechanisms that contribute to differences between men and women, including, for example, prenatal or early perinatal exposure to androgenic steroids, which affects the interdisciplinary differences in brain anatomy and subsequent behavioral, cognitive or personality factors, also give rise to variability within one sex. People therefore differ within one sex to the extent that they have developed features typical of their own or opposite sex, and we are talking about sexual characteristics or atypicalities. This is often detected by a retrospective assessment of the degree of gender nonconformity in childhood, which appears to be a particularly strong, though not a perfect, predictor of sexual orientation in adulthood.

The aim of the study was to test differences in male and female olfactory abilities in relation to sexual orientation and gender nonconformity in childhood. Participants in this study were identical to the sample of young adults from the previous study (Havlíček et al., 2012, Study 2). They stated their sexual orientation on the seven-point Kinsey scale (0 = exclusively heterosexual, 6 = exclusively homosexual), which included either a heterosexual group (0 or 1, N = 73, 41 men) or a non-heterosexual group (2-6; N = 83, 48 men). To assess the level of gender nonconformity in childhood, participants completed a Czech-language version of the Childhood Gender Nonconformity Scale and their olfactory abilities were tested (identification, discrimination and thresholds) using Sniffin ‘Sticks.

The results have shown that heterosexual men have a lower ability to identify odors than non-heterosexual men  and than heterosexual and non-heterosexual women, and also a worse ability in odour discrimination than non-heterosexual men. However, if CGN scores were also included in the analyzes, gender nonconformity in childhood and not sexual orientation proved to be a significant predictor: gender nonconformity in childhood predicted the ability to identify smells in men, with gender-nonconforming men outnumbering gender-conforming men. In women, the CGN predicted the olfactory sensitivity score: gender-conforming women showed greater sensory sensitivity than gender non-conforming women, although the overall model was not significant. Since the ability to identify odors largely depends on the so-called verbal fluency in which non-heterosexual men outperform heterosexual men, the next studies should show whether or not is the better verbal fluency responsible for the better results of non-heterosexual men in the odour identification test. Gender nonconformity in childhood is also associated with, among other things, gender-atypical preferences. These can be a source of experience that is more typical of the opposite sex. Earlier research suggests that women generally have better olfactory capabilities due to, among other things, greater smell and odour experience, as they tend to activities rich in olfactory stimulation more than men. However, this could apply not only to gender-conscious women but also to gender-non-conforming men.