The Evolutionary Cause of Body Part & Clothing Fetishism: Sexual Dimorphism, Fertility, and Disgust Inversion

The Evolutionary Cause of Body Part & Clothing Fetishism: Sexual Dimorphism, Fertility, and Disgust Inversion

Author: Cloudfindings

Date: April 16 2025

Cite as: Cloudfindings (2025) The Evolutionary Cause of Body Part & Clothing Fetishism: Sexual Dimorphism, Fertility, and Disgust Inversion. Cloudfindings. cloudfindings.io/papers/partialisms.pdf

Why is it so common for people to have sexual interests in things that don’t seem sexual? What is the appeal? I first answered this question broadly in Cloudfindings & Younas (2024), where I put forth and mostly proved a new model explaining a wide range of unusual sexual interests as having the same causes of “normal” sexual interests with coherent evolutionary & biological explanations. In this paper, I focus particularly on partialisms, or sexual interest in specific body parts and clothing, and fully explain why all different targets of partialisms occur.

Sexual Dimorphism, Attractiveness & Fertility

What makes someone look attractive? Numerous studies have shown that for the sex a person is attracted to, the perceived attractiveness of a member of that sex is in part determined by how much the characteristics of their appearance are typical of the sex they are attracted to (e.g., facial hair) (Fiala et al. 2021)(Perrett et al. 1998). Sex typical variation of observable characteristics in a species is called sexual dimorphism - for example, men tend to grow more facial hair than women do in humans, making facial hair sexually dimorphic. In other words, women who look more like women are more attractive to people that are attracted to women, and the reason for this is because it indicates important factors in choosing mates such as fertility and health (Perrett et al. 1998). While some more dimorphic than others (e.g., genitalia), all body parts are sexually dimorphic in some way, this of course meaning there will be preferences for characteristics in all parts of the body based on sexual dimorphism, even if they aren’t overtly “sexual”. 

Dictionary Example: Sexual Interest in Feet

Sexual interest in feet is of particular interest for studying due to its high prevalence, it's widely considered bizarreness, and a clear sex difference in the prevalence of this sexual interest. As it turns out, the shape of human feet is very sexually dimorphic - Stankovic et al. (2018) found that the overall shape of a person's foot is explained 90% by whether they are male or female - and that male feet vary from female feet in that female feet have smaller ankle width, a hallux valgus, narrower achilles tendon, a higher arch, and narrower heel, and that the first two largest dimensions of variation in foot shape were predicted most strongly by a person’s sex, over other variables such as shoe size and sport activity. Another study found that 27 measured aspects of foot shape variation (such as length, heel width, first toe angle, little toe height) had mostly medium to large differences between the sexes, for example 73% of women have a higher first toe angle than the average man, 88% of men have a larger heel width than the average woman, and 98% of men have a longer foot than the average woman (Saghazadeh et al. 2015). Does a more female-typical foot shape indicate a more suitable mate in terms of fertility and health? According to Fessler et al. (2012), when men were shown images of feet and asked to rate how attractive they thought the woman was based on the image, women with more female-typical feet were rated as more attractive. It has been shown that sex hormones (which influence fertility and expression of sex-typical characteristics) influence foot shape while growing in puberty (Balzer et al. 2019), and that less feminine foot shape is an indicator of older age (after puberty) which correlates to reduced fertility and health (Echeita et al. 2016). High BMI also influences foot shape to be less feminine (Domjanic et al. 2013). Cloudfindings & Younas (2024) found that attraction to men correlated negatively with sexual interest in feet, further supporting that sexual interest in feet is related to selection of fertile and healthy females, which foot shape is a significant indicator of.

Disgust - From Attraction to Arousal

So, women with more feminine feet are more attractive. How does this translate to sexual arousal? Cloudfindings & Younas (2024) found that the degree to which a body part is considered disgusting or private directly related to the degree to which it is sexually arousing in the context of a sexually desired partner and situation (e.g., an average straight man would enjoy kissing an attractive young woman but not an old man). Feet are widely considered disgusting, and this is in part why this sexual interest is confusing to people (Rees 2022) - however, it is the fact that they are disgusting (and subject to variation in perceptions of attractiveness based on how feminine they look) that makes them able to be sexually arousing. If feet, among other body parts, are relevant to a person's attractiveness, why do some people have fetishes and not others? Cloudfindings & Younas (2024) showed that sex drive predicts the threshold for something considered disgusting to become arousing and how many unusual sexual interests a person has - someone who is completely asexual might even find kissing gross and hard to understand why someone would enjoy kissing, and an extremely hypersexual person might find it arousing to bathe in sewage. Legs, which are commonly seen as sexually appealing (Smith 2013), are an example of a body part with high sexual dimorphism (such as in muscle attributes), but are considered less disgusting and private, therefore would typically be less arousing than a more disgusting partialism, but still a target of attraction and sexual interest. 

Sexual Dimorphism and Other Partialisms

Sexual interest in bodily fluids and waste are likely unrelated to sexual dimorphism, but still likely to be arousing or disgusting depending on the attractiveness of the person it is coming from, if the person has a high enough sex drive for the disgust to be transformed into arousal. Asexual people may be disgusted by all sexual interests, but still have a gauge of the attractiveness of body parts in the sex they are attracted to (sexual orientation is not dependent on sex drive). Unusual sexual interests related to body parts but not the body itself (e.g., leggings) also likely emerge based on sexual dimorphism, for example high heels are mostly worn by women and seen commonly as sexually appealing (Watkins et al. 2020), and may become sexually arousing to someone with a pre existing sexual interest in feet. Sexual dimorphism also influences attractiveness in relation to things like colors, women being perceived as more attractive if wearing red (Wen et al. 2022), or general styles of dress such as goth or alternative styles which are highly female typical, explaining the phenomenon of some men having a preference for "goth" or "alt" women (Nally 2018). Not to focus all on sexualization of women, women more often have sexual interest in the hands of men (Cloudfindings & Younas 2024), and men with more attractive hands are seen as more attractive overall (Kościński 2011). Men with more muscular body parts are also seen as more attractive to women (Frederick & Haselton 2007), and this may facilitate partialisms in women similarly to men, such as toward legs.

Conclusion

Overall, this solves the previously unexplained - or poorly explained existence of partialisms - feet, hands, legs, clothing, etc, with a full explanation grounded in empirical findings and evolutionary theory.

Cloudfindings & Younas (2024) Explaining Paraphilia: A Novel Model Explaining A Wide Range of Sexual Interests Continuous With Normal Sexuality. Cloudfindings. cloudfindings.io/papers/paraphilia.pdf

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