Last week, a new study on the association between pubic hair grooming and sexually transmitted infections (STI) was published in the journal Sexual Transmitted Infections. Because I’ve published research related to pubic hair removal, several journalists contacted me to weigh in on the study and contextualize it for their publications, which I was happy to do. However, the widespread interest in the study – not to mention the complexities of researching this aspect of interacting with one’s own genitals – suggested to me that it would also be a useful topic for Kinsey Confidential, and so here we are.
The new study is titled “Correlation between pubic hair grooming and STIs: results from a nationally representative probability sample” and it was conducted by researchers from the University of California – San Francisco, the University of Texas, and Washington University. Its methods of data collection are sound; their probability sample was obtained through working with GfK’s KnowledgePanel, which (in full disclosure) my research team and I have worked with several times, with GfK being one of the few companies to offer web-based US nationally representative probability samples. [More on these methods on the GfK website.]
What did the study find? In short, they found a relationship between pubic hair grooming (and certain ways of looking at it – such as how much hair is removed and the frequency with which one grooms their hair) and some but not all sexually transmitted infections (STI). They found “extreme grooming” (as they called it; total removal 11+ times in a year) associated with lifetime STI risk but no association with frequency of grooming and lifetime STI risk.
A challenge with these data, however, is that they rely on people’s self-reports of ever having had an STI rather than clinical data. Why is this important? As the authors indicate themselves early in the paper, about half of Americans will contract an STI. However, in their sample, only 14% of groomers and 8% of non-groomers reported ever having had an STI. As a survey researcher myself, I note the large gap between the proportion of Americans we know have STIs and the proportion who reported ever having had one. Does that means that the survey respondents were dishonest? Not necessarily. There were likely some respondents who said they’d never had an STI when in fact they knew they had. It’s also possible that some respondents didn’t know they had an STI (not everyone gets diagnosed) or didn’t know what it was they were diagnosed with (some people don’t recall what a doctor or nurse told them). The bottom line, however, is that there may be other explanations for the study findings. It may be that groomers are more likely to get an STI, but it also may be that groomers are more likely to be proactive about their sexual health, to seek sexual health care, to get STI testing, and/or to remember healthcare diagnoses linked to their sexual health.
Having reviewed the study findings, it also seems that respondents were generally unaware of or under-reported their STI history – which suggests concerns with the validity of the self-report data. For example, herpes and HPV are very common STIs in the US and yet they were each reported by only 1% of non-groomers and 3% of groomers. Similarly, chlamydia (the most common bacterial STI in the US) was only reported by 2% of non-groomers and 5% of groomers. In contrast, syphilis is somewhat rare in the US and yet it was reported by nearly the same percentage of Americans (0.7% of non-groomers and 1.3% of groomers) as HPV, herpes, and chlamydia. Something doesn’t add up! [If pressed to explain this difference, I might guess that a syphilis diagnosis might be more memorable to individuals, especially given its potential severity if left untreated, and thus perhaps it is more accurately reported in survey research than other STIs.]
If we assume that the study findings are correct, however, then we need to ask why pubic hair grooming may be linked with risk of some but not all STIs. The researchers noted that it’s possible that certain kinds of grooming (for example, shaving) can cause very small tears in the skin that may increase the risk of STI transmission. If found to be true, they suggest that it could influence health education and/or recommendations for waiting a certain length of time after grooming before having sex (as someone who studies sexual behavior, I feel the latter is highly unlikely since we know from other research and from teaching that people tend to groom in preparation for sexual activity that’s about to occur).
The authors note that it also may be that having had an STI may be associated with people changing their pubic hair grooming behavior. This is also possible, particularly given the stigma that some people experience related to STIs. Once diagnosed with an STI, some people may worry about feeling “dirty” and try to become “clean” by grooming their pubic hair (some qualitative research has found that people cite hygiene among their reasons for pubic hair removal).
If pubic hair grooming does somehow cause an increase in STI risk, should you change anything about your behavior? Some of the differences in reported STIs between groomers and non-groomers were quite small. For example, 8% of “extreme groomers” (those who removed all of their pubic hair more than 11 times per year) reported ever having had chlamydia versus 5% of “non-extreme groomers” – a difference that was statistically significant. Whether this difference is meaningfully significant to you is a personal question. [And again: it may be that “extreme groomers” are simply more vigilant about their sexual health more generally, not that they are necessarily more prone to STI risk for biological reasons.]
Whether you alter your grooming practices based on this one study is up to you. The study did not address much about sexual behavior (other than the number of lifetime partners), which is a significant limitation. For example, we don’t know much about survey respondents’ condom use, type of partners (generally relational versus generally casual), preferred or common sexual repertoire, and so on – any of which could negate the relationship between pubic hair grooming and some but not all STIs. Past research (including that of my own research team) has found that total removal of pubic hair is more common among people who are not in monogamous relationships, for example, underscoring the complexities of how people may make decisions about pubic hair style based on their sexual lives. I’d also note that many people change their grooming behaviors from time to time. Some people who used to remove most or all of their pubic hair no longer do, and vice versa. And some people who used to remove their pubic hair frequently go through periods of little to no removal. Similarly, sexual behavior patterns and sexual frequencies change throughout life and so correlating two “moving target” variables over a lifetime is challenging at best.
The authors themselves acknowledge the need for subsequent research to address these many questions and I look forward to seeing more of such work in print. Find the original study on the journal’s website.