Debunking Denialism

Defending science against the forces of irrationality.

Dispelling Myths about Human Female Sexual Anatomy and Physiology

Justifiably angry

From virginity-obsessed religious theocrats and fake sex gurus who fetishize over their own misunderstandings of human anatomy for financial gain to serious scientists publishing methodologically flawed research that turn out to be non-reproducible and unscrupulous doctors promoting untested and potentially dangerous surgical procedures, the scientific realities of human female sexual anatomy and physiology has come under fire from a diverse range of sources. Aggravated by media attention and bad science journalism, this area has become filled to the brim with a great deal of distortions and misconceptions. It is time to strike back.

The “evidence” for the existence of a female G-spot consists mostly of anecdotes and a flawed study that did not even save a histological sample, so it is most likely not a general anatomic feature in women. G-spot amplification surgeries have not undergone rigorous clinical testing and carries serious potential risks. Many women cannot achieve orgasm by just having vaginal penetration. Virgin tests are based on discredited notions about vaginal anatomy and virginity. Finally, there is very little credible evidence that menstrual synchronization occurs when women live together for an extended period of time and the fact that most of these studies could not be replicated suggests that initial findings were capitalizations on chance.

Fact #1: The “G-spot” probably does not exist as a general anatomic feature

The G-spot is a hypothesized distinct anatomical area situated in the anterior vaginal wall that is said to incite especially intense sexual pleasure when stimulated. However, it has proved to be elusive to identify this area using scientific methods. Despite this, some women are convinced that this area exists and the notion has been quickly exploited by charismatic sex gurus, popular women’s magazines and unscrupulous surgeons.

However, the scientific state of knowledge differ substantially from popular imagination. Two recent reviews by Puppo and Gruenwald (2013) and Kilchevsky et. al (2012) converge on the general conclusion that the G-spot is a myth without any anatomical reality. Puppo and Gruenwald (2013) state that “All published scientific data point to the fact that the G-spot does not exist” and Kilchevsky et. al (2012) concludes that:

The distal part of the anterior vaginal wall appears to be the most sensitive region of the vagina, yet the existence of an anatomical “G-spot” on the anterior wall remains to be demonstrated. Objective investigative measures, either not available or not applied when Hines first published his review article over a decade ago, still fail to provide irrefutable evidence for the G-spot’s existence. This may be, in part, because of the extreme variability of the female genitalia on an individual level or, more likely, that this mythical location does not exist.

A recent study by Ostrzenski (2012) was herald in the media as the final proof for the existence of the G-spot. However, that study was nothing more than an N = 1 dissection of a dead 81-year-old woman and they did not even save the tissue sample. They simply used “visual inspection” to decide that they had found the elusive G-spot. Here is how Puppo and Gruenwald (2013) describes the study:</p

In a recent attempt to define a so-called G-spot, Ostrzenski extracted parts of the anterior vaginal wall of the cadaver of an 83-year old woman and called it the G-spot: “The anatomic existence of the G-spot was documented in this study with potential impact on the practice and clinical research in the field of female sexual function.”. The author wrote: “The G-spot was identified as a sac with walls that grossly resembled the fibroconnective tissues, was easy to observe, and was a well-delineated structure”; however, no histologic studies of the samples were offered. The author also stated: “The G-spot gene has been identified,” but this is a misreading of the reference he quotes. It seems totally inappropriate to claim that the existence of a G-spot has been “documented” on the basis of one cadaver dissection by a physician who is actively involved in a commercially oriented institute.

In other words, Ostrzenski also has a considerable conflict on interest, as he himself promotes and performs G-spot amplification surgeries (Hall, 2012).

Fact #2: “G-spot amplification” is untested and dangerous pseudoscience

G-spot amplification involves the injection of collagen into the anterior vaginal wall. The idea is to enhance the sensitivity G-spot and increase sexual pleasure. However, according to Puppo and Gruenwald (2013), there are no medically valid reasons for this procedure, it is not approved by the FDA, it is explicitly rejected by the American College of Obstetricians (2007) and Gynecologists, there are no peer-reviewed publications demonstrating safety or efficacy, and it has substantial risks, including dyspareunia (i. e. painful sex).

Fact #3: A considerable proportion of women cannot orgasm through vaginal penetration alone

From the steamy alternative history novels in the Earth’s Children series to the average pornographic clip on the Internet, vaginal intercourse among heterosexuals seem to frequently lead to female orgasm on its own. Although clitoral stimulation sometimes occur in these different media, vaginal intercourse is primarily centered around the repetitive, in-and-out thrusting motion. However, this is a very misleading picture, because the vast majority of heterosexual women cannot reach orgasm during vaginal penetration alone. In a review paper on orgasm, Mah and Binik (2001) summarized some of the previous research like this:

The majority of women indicate that clitoral stimulation is important for achieving orgasm. Fisher (1973) reported that on average, 63% of sampled women reached orgasm through clitoral stimulation followed by intercourse, and another 35% through clitoral stimulation before or after their partner’s coital orgasm. Women rated clitoral stimulation as at least somewhat more important than vaginal stimulation in achieving orgasm; only about 20% indicated that they did not require additional clitoral stimulation during intercourse, and 12% considered vaginal stimulation more important than clitoral stimulation.

The estimates discussed in the above review paper differ, but generally land around 70-80%. Similarly, Kammerer-Doak and Rogers (2008) explain that:

Most women report the inability to achieve orgasm with vaginal intercourse and require direct clitoral stimulation. About 20% have coital climaxes, and 80% of women climax before or after vaginal intercourse when stimulated manually, orally, or with a vibrator or other device. Only 30% women almost always or always achieve orgasm with sexual activity in contrast to 75% of men.

Far from the imagery and beliefs that step from popular depictions of vaginal intercourse, most heterosexual women cannot orgasm through vaginal intercourse alone.

Fact #4: “Virgin tests” are flawed

The hymen, or the vaginal corona as it is sometimes called, is a collection of small folds of mucosal tissue near the vaginal opening. In many cultures, such as fundamentalist Islamic and Christian societies, an intact hymen is considered to be positive proof of virginity (Tschudin et. al, 2013). However, as Cook and Dickens (2009) points out, this is not accurate:

Named after the god of marriage in classical Greek mythology, the hymen is presumed to be broken at a woman’s first experience of sexual intercourse, and its intact condition is so taken to represent virginity. A hymen may become ruptured or torn in several other ways, however, including vaginal insertion of objects such as tampons, vigorous sporting activities, surgical procedures, and falling on sharp objects.

There are also rare cases were girls are born without a hymen (MedlinePlus, 2013), so the presence of absence of a hymen is not a reliable indicator for virginity.

There are other alleged virginity tests which involve inserting one or two fingers up the vagina to check the size and the level of looseness. According to Human Rights Watch (2010), this has been used by some Indian medical and legal authorities to determine if rape victims are telling the truth or not. If the vagina is small and/or firm, they conclude that no sexual activity has occurred. If the vagina is large and/or loose, they may conclude that an unmarried women is sexually promiscuous and thus have an unreliable moral character. In reality, finger tests are flawed for much the same reasons as the hymen test: the size and laxity of the vagina are affected by many other factors unrelated to virgin status.

Fact #5: Scant scientific evidence for menstrual synchronization in humans

In 1971, the researcher Martha McClintock published a paper in Nature suggesting that women who live together seem to undergo menstrual synchronization because of a pheromone-mediated mechanism (McClintock, 1971). However, dark clouds soon started to appear on the horizon. Although some initial studies seemed to replicate McClintock’s initial findings, later studies started finding inconsistent results. First, the hypothesized pheromone-mediated mechanism took a serious blow when e. g. Quadagno and collegues (1981) found that close female friends, but not female neighbors, underwent menstrual synchronization. Second, several methodological criticisms were leveled against McClintock and the classical paradigm of menstrual synchronization. Third, many later studies with improved methodology failed to replicate menstrual synchronization.

A recent review by Harris and Vitzthum (2013) explains that:

MS is often assumed to be a well-documented feature of women’s biology but, in fact, there is surprisingly little (if any) undisputed evidence to support the existence of any mechanism that functions to create synchrony among women’s cycles. Rather, apparent synchronization is readily attributable to chance convergence arising from the finite and variable length of menstrual cycles and the rules of probability. Thus, given an average cycle length of 28 days, the maximum number of days by which two women can differ in menstrual onset is 14 days, and the average difference is only seven days. In light of the evidence presented earlier on the natural “irregularity” of women’s cycles (i.e., about half or more of women who claim to have “regular” cycles, in fact, have a range in segment length of at least six days and about a quarter have a range greater than two weeks), it is hardly surprising that menses onset is coincident at some time or another in a pair of women.

Harris and Vitzthum (2013) go into additional detail about the methodological and statistical flaws of the studies purporting to show menstrual synchronization. This included the incorrect usage of a statistical significance test:

For example, McClintock appears to have incorrectly used the Page test for ordered hypotheses with multiple treatments (she used the same groups of women repeatedly instead of independent treatments), making it impossible to evaluate the true level of significance of her reported findings.

…treating overlapping groups as mutually exclusive:

McClintock (1971) assumed in her analyses that “roommates” and “closest friends” were mutually exclusive groups, which they may not have been, an assumption that undermines the validity of her statistical tests.

….as well as basic calculation errors:

McClintock (1971) also appears to have miscalculated the menses onset dates for the study subjects, which artificially inflated the calculation of the initial divergence among subjects (Wilson, 1992). As a consequence, the study appeared to show significant decreases in the difference between the timing of menses onset, when in fact any convergence was reasonably attributable to chance.

They conclude that:

An appreciation of the likely patterns of ovarian cycling throughout much of human evolutionary history (until the 20th century) coupled with data on the extraordinary variation within and among contemporary women in cycle length quickly leads to a nagging doubt regarding the likelihood of MS sensu stricto. Add a good dose of probability theory and the fact that reasonably well designed studies have failed to support the MSH, and one is left wondering why so much attention has been given to searching for elusive mechanisms and constructing convoluted evolutionary scenarios. In light of the lack of empirical evidence for MS sensu stricto, it seems there should be more widespread doubt than acceptance of this hypothesis.

A similar issue related to the failure to replicate hit studies on menstrual or estrus synchronization in many non-human animals (Hall, 2011).

Objections anticipated:

This post is likely to be considerably more controversial than the topics this website usually cover, here a short list of some anticipated objections with their responses.

—> But I have a G-spot, I can feel it!

The scientific issue is not if single individuals have a G-spot, but whether it is a general anatomic feature common to most women. Thus, these kinds of anecdotes cannot be considered sound scientific arguments.

—> I had G-spot amplification and it worked for me!

The bottom line is that G-spot amplification is untested, unapproved and has considerable risks. The fact that you have a subjective experience of it working is an anecdote, not scientific evidence. How do you know it was not because of the placebo effect? Consider the example of arthroscopic surgery for knee osteoarthritis. At a time when this procedure was carried out over half a million times per year and around half of all patients reported pain relief, Moseley et. al (2002) showed that outcomes were not better than a sham surgery. If around a quarter of a million people can be fooled by the placebo effect of a certain surgical procedure per year, then why can’t you?

—> Me and my roommate synced up!

So? Since studies have failed to find evidence for menstrual synchronization in humans, those that purported to show synchronization could not be replicated and the fact that menstruation is not as regular as most people think, there is very little reason to believe that it cannot be attributed to chance.

—> But you are a man! You arrogant pronunciations on the experience of women does not count!

Good thing that my claims are backed up by the scientific literature then. Also, if you had paid attention to the references, many of these papers were written by women.

—> Virginity brings honor, which is very important in some cultures

So? That does not mean that virginity tests are valid or reliable indicators of virginity. All you are doing is reaffirming that virginity tests (and the obsession over virginity) are based on cultural superstition. The fact that these cultural obsessions exits (albeit in different forms) across cultures is irrelevant. A common superstition is still just a superstition.

References:

Committee on Gynecologic Practice, American College of Obstetricians and Gynecologists. (2007). ACOG Committee Opinion No. 378: Vaginal “rejuvenation” and cosmetic vaginal procedures. Obstet Gynecol. 110(3):737-8.

Cook, R. J., & Dickens, B. M. (2009). Hymen reconstruction: Ethical and legal issues. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 107(3), 266-269.

Hall, H. (2011). Menstrual Synchrony: Do Girls Who Go Together Flow Together?. Science-Based Medicine. Accessed: 2014-01-01.

Hall, H. (2013). G-Spot Discovered? Not So Fast!. Science-Based Medicine. Accessed: 2014-01-01.

Harris, A. L., & Vitzthum, V. J. (2013). Darwin’s Legacy: An Evolutionary View of Women’s Reproductive and Sexual Functioning. The Journal of Sex Research, 50(3-4), 207-246.

Human Rights Watch (2010). Dignity on Trial. Accessed: 2014-01-01.

Kammerer-Doak, D., & Rogers, R. G. (2008). Female Sexual Function and Dysfunction. Obstetrics and Gynecology Clinics of North America, 35(2), 169-183

Kilchevsky, A., Vardi, Y., Lowenstein, L., & Gruenwald, I. (2012). Is the Female G-Spot Truly a Distinct Anatomic Entity? The Journal of Sexual Medicine, 9(3), 719-726.

Mah, K., & Binik, Y. M. (2001). The nature of human orgasm: a critical review of major trends. Clinical Psychology Review, 21(6), 823-856

McClintock, M. K. (1971). Menstrual Synchrony and Suppression. Nature, 229(5282), 244-245.

MedlinePlus. (2013). Developmental disorders of the female reproductive tract. U. S. Library of Medicine. Accessed: 2014-01-01.

Moseley, J. B., O’Malley, K., Petersen, N. J., Menke, T. J., Brody, B. A., Kuykendall, D. H., . . . Wray, N. P. (2002). A Controlled Trial of Arthroscopic Surgery for Osteoarthritis of the Knee. New England Journal of Medicine, 347(2), 81-88.

Ostrzenski, A. (2012). G-Spot Anatomy: A New Discovery. The Journal of Sexual Medicine, 9(5), 1355-1359. doi: 10.1111/j.1743-6109.2012.02668.x

Puppo, V., & Gruenwald, I. (2012). Does the G-spot exist? A review of the current literature. International Urogynecology Journal, 23(12), 1665-1669. doi: 10.1007/s00192-012-1831-y

Quadagno, D. M., Shubeita, H. E., Deck, J., & Francoeur, D. (1981). Influence of male social contacts, exercise and all-female living conditions on the menstrual cycle. Psychoneuroendocrinology, 6(3), 239-244.

Tschudin, S., Schuster, S., Dumont dos Santos, D., Huang, D., Bitzer, J., & Leeners, B. (2013). Restoration of Virginity: Women’s Demand and Health Care Providers’ Response in Switzerland. The Journal of Sexual Medicine, 10(9), 2334-2342.

Image credit: geoX.

3 responses to “Dispelling Myths about Human Female Sexual Anatomy and Physiology

  1. Jacqueline January 1, 2014 at 22:16

    This is an excellent article. You did a fine job of preemptively addressing objections, though I’m having trouble imagining any legitimate, objective criticisms that could arise. The ones you mentioned are all blatantly subjective or logically fallacious.

    • Emil Karlsson January 2, 2014 at 00:36

      It is conceivable that someone could make an objection based on some of the nitty-gritty research details related to the G-spot, the proportion of women who can reach orgasm through vaginal penetration only or menstrual synchronization. For instance, the response rate to some of the studies on orgasm through vaginal penetration only could have been higher, but even if the true proportion was slightly off 80% it wouldn’t change the general conclusion that a majority of women cannot achieve orgasm through vaginal penetration alone.

      For virgin tests and G-spot amplifications, I have a much harder time coming up with conceivable objections that have any credibility. I doubt they exist.

    • Jacqueline January 3, 2014 at 23:27

      You’re right, I suppose the ideas or outcomes themselves could be challenged, but doing so in a legitimate capacity would probably require the critic to either carry out or facilitate new experiments/studies. Regardless, different results would not invalidate your arguments against the methods and inconsistencies in the studies that were referenced in your article.

      Keep up the good work. I hope to read more from you in the future.

Follow

Get every new post delivered to your Inbox.

Join 218 other followers

%d bloggers like this: