The Average Human Vagina

By Jenny Morber, for DoubleXScience 

Do you secretly suspect that your vagina is above average? It may be, but how would you know? Though ladies share a lot, one thing that we tend to keep to ourselves is the appearance of our female anatomy. (Which we hardly ever see anyway. Pop quiz ladies: could you recognize your own in a line-up?) So how do you know if your lady parts are normal? Fortunately, researchers are on the case.

Before we dig in, let’s take a minute to define some terms. ‘Vagina’ and ‘vulva’ are not two words for the same anatomy. The word vagina (DXS explainer here) is derived from the Latin word for “sheath”. It is the internal cavity within the female body*. (A high school anatomy teacher was recently investigated for using this word in an anatomy class. Because, of course, 10th -graders don’t have vaginas, aren’t interested in vaginas, and certainly have no need to know what vaginas are. Vagina: it’s not a dirty word.)

Vulva denotes the external female genitals – the lady parts that you see when you stand naked in front of a mirror. The vulva includes several components, including the labia majora (outer lips), labia minora (inner lips), mons pubis (the bony protuberance), clitoris, the opening of the vagina, and others. Wikipedia describes the labia majora and labia minora as the vulva’s “double door” that protects the vagina, which makes me imagine a stately entrance to a library. It’s a nice mental image, if perhaps not the most accurate.

So, are you normal? Are you average? Yes. No. Most likely. It turns out that there is so much variation among female anatomy that doctors, surgeons, and researchers find it difficult to define exactly what normal is – or even if it exists. And a few at least have been trying.

The Vagina

 In 1991 a group of three researchers published a paper that described a method for casting a mold of the vagina using material more commonly used to make dental impressions. In short, liquid polymer goo is injected into a willing woman’s vagina with a kind of caulk gun. She waits ten minutes. Then with the help of KY, squatting and pushing, and the string from a tampon that was inserted before the material dried, the mold is removed. Though this paper included only two participants, a few years later the same researchers (plus a couple of others) published another study that examined vaginal molds of 39 women. In these women, all Caucasian, vaginal lengths ranged from almost 7 to almost 15 centimeters (2.75–6 in) with diameters between 2.4 and 6.5 cm (~1–2.5 in). A later study classified the diversity of vaginal shapes: conical, parallel sides, heart, slug, and pumpkin seed. (I can’t be the only one hoping that my vagina looks like a pumpkin seed instead of a slug.)                                          

                                      Pelvis 113721

And if you are thinking that maybe you really ARE above average because you have evidence that a seven inch penis can fit in yours, please remember that these studies are performed on women who are not sexually aroused. The vaginal wall lengthens during arousal as increased blood flow pushes the cervix and uterus upward. How do we know this? Well, MRI sex videos help (NSFW).

To me, the most interesting paper to use the mold technique compared vaginal shapes among 23 African-American, 39 Caucasian, and 15 Hispanic women. The researchers found that the Hispanic ladies’ vaginas were wider overall, longer in the back, and shorter in the front than the vaginas of the other women. The study also noted that the Caucasian women had a much larger vaginal opening than did the African American women. Fascinating.

Of course, molds don’t always perfectly capture the likeness of the intended object. In 2006, a group of doctors and researchers employed MRI scans in an attempt to better quantify the normal vagina. Again they found that “No one dimension characterized the shape of the human vagina.” Vagina quantification fail.

Until these studies, knowledge of female pelvic anatomy was largely based on old descriptions of a few female cadavers. I for one am a little disturbed that it has taken so long for basic female anatomy to become interesting enough for serious study. But we haven’t even gotten to the best part yet. Next up, the human vulva.

The Vulva

If you are like me (and according to the research, you likely are if you were born with a vagina), what you know about the appearance of the human vulva comes from caring for infants and children, self-study, and porn. It turns out that these are not the richest sources. Just like the vagina, the human vulva is wonderfully diverse. Some vulvas have tiny labia minora. Some have very long labia minora. Some have tight labia majora, and others have “phat lips.”

In 2005, after getting consent from premenopausal women who would be under general anesthesia for other reasons, a group of researchers examined the appearance and dimensions of 50 women’s genitalia. The authors measured clitoral size, labial length and width, color, vaginal length, distance from clitoris to urethra, and distance from the bottom of the vagina to the anus. The paper’s results state, “A wide range of values were noted for each measurement. There was no statistically significant association with age, [number of vaginal births], ethnicity, hormonal use, or history of sexual activity.” Once again, female genitalia are too diverse to be neatly quantified.

(You may note a discrepancy between this study, which found no association between race and vaginal length, and the one discussed above, which did. The authors do not discuss the discrepancy or even cite the previous study. Possible reasons for the discrepancy could include a smaller sample set in this work (50 women instead of 77), or differences in methods. Here, researchers inserted a vaginal swab to measure length, and remember, these participants were under general anesthesia.)

The authors observe, “In general, there are surprisingly few descriptions of normal female genitalia in the medical literature. In contrast, measurements for male genitals are widely available and were published as early as 1899.” And perhaps most shocking: “…even some recent text books of anatomy do not include the clitoris on diagrams of female pelvis. ” In 2005!

Complicating things for the researchers is that female genital appearance is not static. The vulva changes several times during a woman’s life. We aren’t supposed to look at age 35 like we did at age nine. But often, media sources give women the opposite message. Where do many women get ideas about how their lady parts should look? Porn, of course.

                                        Obstetrical Examination 1822

In 2011, a paper in the Journal of Sex Research took a look at how female genitals are portrayed through magazine pornography. Using a coding system to evaluate physical characteristics, the authors (helped out by undergraduate females) examined 647 centerfolds in Playboy magazine. Between 1953 and 2007, the visibility of the mons pubis and labia majora increased, hip sizes and BMI decreased, visibility of pubic hair decreased (due to shaving and waxing), and only two photographs displayed visible labia minora, both pink, and neither prominent.

A closer look at multiple images in Playboy between 2007 and 2008 found similar results. The authors point out the “striking parallel between Barbie dolls and Playboy magazine models in terms of their portrayal of female sexuality.” They caution, “Playboy photographs have the potential to condition readers to experience sexual arousal in response to viewing or fantasizing about girls and young women.” Keep in mind that as of 2011, Playboy magazine’s national circulation exceeded 3 million copies a month, and over 19% of subscribers were female. Playboy magazine at least seems to be asserting that there is such a thing as a normal vulva, and it looks like that of a pre-pubescent girl.

Women are getting the message. Surgeries for labia reduction doubled in the UK between 1999 and 2005. In a retrospective study of six women who had undergone cosmetic labial reduction, the authors remarked, “A theme that was present for all the women was that of ‘normality’, which was returned to throughout the conversations, with the women feeling as if their genital appearance prior to surgery was ‘odd’, ‘weird’ or made them ‘freaks’.”

Another study published this year examined online advertisements for female genital cosmetic surgery and found scanty reference to appearance diversity, minimal information on risks and outcomes, and no mention of other ways to manage body dissatisfaction. On websites that featured before and after images, in all cases the “before” pictures represented normal labia. In response to claims that these surgeries can improve comfort, the authors remind us that “…both men and women may experience genital discomfort, but only women are encouraged to have their external genitalia excised as a solution.” And the anxiety is trickling down: Research has documented normally developing girls as young as nine requesting labia reduction surgery.

Also worrying is that there are few medical standards and little oversight for these procedures. Websites advertising female genital cosmetic surgeries often cite increased sexual satisfaction as a benefit, but there is little evidence to suggest that they improve sexual function. Instead, surgeries on areas such as the labia and clitoris may cause damage to the vascular and nerve supply. Because a surgeon who performs labia reduction surgeries can earn as much as $250,000 a month, the practice is becoming riddled with inexperienced doctors. In one article, a surgeon estimates that 20% of his business comes from correcting mistakes made by other practitioners.

Still, many women report satisfaction after their surgeries. In a questionnaire-based survey of nearly 170 women, 89% percent of responders who underwent labia reduction surgery were happy with the esthetic result, and 93% were happy with the functional result. Large labia minora can cause real problems, both psychological and physical, including irritation, pain, chronic infection, and sexual difficulties. Many women have spoken positively about their surgeries, testifying that they are more confident in new relationships and less preoccupied during sex.

Other women are pushing back against the stereotype that we should all look tight and trim and homogeneous. There is now a “labia pride” movement that works to expose women to real genital diversity so that they do not judge themselves by unrealistic standards. I had no idea how much variation there could be until I visited the website of the Large Labia Project and saw the vulva drawings of Betty Dodson (both NSFW). Who knew that vulvas came in so many colors, shapes, and sizes? Men, too, are speaking up in favor of more flower-like lady parts. Some men prefer longer labia. In Making the Cut, an article on labial surgeries, one man tells the author, “The lips, for me, are a huge turn on.”

Let’s recap. Vaginas and vulvas are so diverse as to defy quantification. Normal doesn’t exist. Porn promotes images of women whose genitals look like pre-pubescent girls. These images have sadly been internalized by members of both sexes, but we no longer have to look to porn to find images of genitalia other than our own. "So ladies, stand up and be proud: most likely your lady parts are both normal and extraordinary. Vaginas (and vulvas too!) are wacky, wonderful and in no way average."

This piece originally appeared on the brilliant DoubleX Science.  It is (enthusiastically and gratefully) republished with permission.

[Jenny Morber is a freelance science writer and editor with diverse and eclectic interests. She holds a PhD in Materials Science and Engineering with a focus on the intersections among nanomaterials, magnetism, and biotech. She lives and works (along with her vagina) in Fairfax, VA.Follow her on Twitter @JRMorber.]

Image credits: homepage and thumbnail, Wikimedia Commons. Exam image in post, also Wikimedia Commons. Pelvic MRI image, (c) Nevit Dilman, via Wikimedia Commons (click to view interactive image), Creative Commons Share Alike license.

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