How Your Cat Could Make You Kinkier

Earlier this week, I wrote an article about how infectious organisms transmitted through sex can potentially alter the sexual behavior patterns of the host. By encouraging the host to engage in more sex with more partners (and/or to have more unprotected sex), the organism has the ability to survive and thrive through increased transmission.

After writing that article, I was reminded of another study I read a few years back that further supports this idea that certain pathogens can manipulate human sexual behavior—and, in this case, potentially even make us even more prone to kink.

A 2016 study published in the journal Evolutionary Psychology looked at whether there is a link between toxoplasmosis infection and kinky sexual interests. Toxoplasmosis is a parasitic disease that can be passed from cats to humans. So why look at it in relation to kinky sex, you ask?

Previous research (nearly two dozen studies, in fact) has shown that this parasite changes behavior in infected mice and rats. Basically, when rodents become infected with toxoplasmosis, it switches off their inborn fear of the scent of cats and, instead, creates an attraction toward it. The researchers refer to this as the “fatal attraction phenomenon” because it puts their lives in danger, given that cats are natural predators of rodents.

To the extent that toxoplasmosis also alters fear circuitry in the brains of humans, one could imagine all kinds of ways this might potentially impact behavior, sexually and otherwise, For example, could this make “edgier” sexual behaviors more sexually appealing? That’s what the authors of this study wanted to explore.

They surveyed more than 36,000 people, but only analyzed data from the subset of 5,828 people who had previously been lab tested for toxoplasmosis and who knew they were either positive or negative.

Participants completed a survey about their sexual desires, behaviors, and preferences. What the researchers found was that people’s attraction to kinky sex did indeed seem to depend upon whether they had been infected with this parasite.

In the words of the study’s authors, “infected subjects expressed higher attraction to nonconventional sexual practices, especially the BDSM-related practices.” Further, infected persons “expressed higher attraction to bondage, violence, zoophilia, fetishism, and, in men, also to masochism, and raping and being raped.”

They argue that the results are consistent with the idea that this parasite alters perceptions of fear and danger in a way that increases openness to kinkier sexual practices. However, they are very clear to say that this effect probably only “slightly increases” tendencies toward kink and BDSM and that “it could hardly be fully responsible for humans’ sexual arousal by BDSM.”

I’ve written extensively on the blog about how common kink and BDSM interests are—in fact, this is one of the most popular sexual fantasies. And people can be drawn to kink for a wide range of reasons (there are at least 8 possible reasons that have been identified in past research).

As a result, it’s important to reiterate that even if toxoplasmosis plays some role in developing kinky sexual interests, it’s likely to be quite small. In other words, none of this is to say that kink in general is the result of some disease process or that it’s necessarily unhealthy.

It’s also worth noting that this isn’t the only research to find that toxoplasmosis may contribute to changes in sexual behavior. I recently came across a different study finding that men infected with this parasite have higher levels of testosterone than non-infected men, suggesting that toxoplasmosis may cause changes in the neuroendocrine system. Elevated testosterone combined with an increased propensity for risk-taking could potentially lay the groundwork for seeking more partners and engaging in more sexual activity—and, given that toxoplasmosis can be sexually transmitted between humans, this would provide a mechanism for the parasite to multiply.

Overall, these results are yet another piece of evidence suggesting that human behavior can potentially be manipulated by microorganisms in ways that we do not consciously recognize.

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To learn more about this research, see:

Flegr, J., & Kuba, R. (2016). The relation of Toxoplasma infection and sexual attraction to fear, danger, pain, and submissiveness. Evolutionary Psychology, 14(3), 1474704916659746.

Borráz-León, J. I., Rantala, M. J., Luoto, S., Krams, I., Contreras-Garduño, J., Cerda-Molina, A. L., & Krama, T. (2021). Toxoplasma gondii and Psychopathology: Latent Infection Is Associated with Interpersonal Sensitivity, Psychoticism, and Higher Testosterone Levels in Men, but Not in Women. Adaptive Human Behavior and Physiology, 7(1), 28-42.

Image Source: 123RF/Vasilii Kireev