• Debate: Does the vaginal orgasm exist? Part 2

    She-RaThis post is part of an on-going debate between myself and Trisha Borowicz of the Science, Sex and the Ladies (SSL) blog. The reader is encouraged to read the earlier posts before this one for proper context. Here are the links.

    Part 1
    Initial post at Incredulous
    SSL rebuttal 
    Part 2
    Incredulous (This post)
    SSL rebuttal

    This post begins Part 2. I would like to thank Trisha for her participation here, and her tireless efforts to promote public understanding and discussion of sexuality. This is a contentious and sometimes emotionally-charged topic that often devolves discussions into personal, anger-fueled fights. Trisha’s stalwart civility and thoughtfulness in the face of sharp dissent is truly admirable. It makes this (hopefully) productive exchange possible.
    As a reminder, this debate has two resolutions in which Trisha takes the pro position and I am taking the con:

    The Statements to be Debated

    1. Masters & Johnson’s  (1966) book Human Sexual Response provides the best scientific description of the definition and nature of orgasm.
    2. Orgasm is caused by direct or indirect stimulation of the clitoral glans/vulvar area in women.

    Trisha maintains that orgasm caused by vaginal stimulation is a myth and lacks an evidential basis. She asserts the above statements are, boiled-down, the reasons we should accept that.


    In my previous post I made two arguments against statement one: (1) that Masters and Johnson 1966 (M&J) is not and should not be considered authoritative about the definition of orgasm and (2) that Trisha misrepresented what M&J’s definition is. In support of (1), I wrote that the study is not considered authoritative about the nature of orgasm and I cited the literature to show this is incontrovertibly true. I said that should not be considered authoritative because of many limitations and flaws which are widely agreed-upon. In support of (2), I wrote that M&J never said their physical measures were a definition of orgasm, only that they were indicators an orgasm had occurred.

    Trisha starts by outlining her support for the statements. I am unsure why this was necessary, since my arguments were replies to her existing writings on the topic. Her reply proper is to be found in the appendix. I find this odd as well, because the whole point of this debate is… the debate, and an appendix is usually where you put important, but secondary, material.

    1.0 Flaws and limitations with M&J 1966

    Trisha said that I object to aspects of the study “in an attempt to discredit their findings about orgasm.” This is incorrect. Any study has inherent limitations and flaws. This is why scientists virtually never take a single paper to be definitive about any new finding. Criticism of limitations and methodological design flaws is normal in research and does not ordinarily discredit a study (though it may, if the flaws are so severe as to render the conclusions unsupported). In fact, my views of M&J are largely in-line with what the authors themselves wrote about their work, its limitations, and its broader import.

    As a published researcher and peer-reviewer, I can say from experience that my criticisms of M&J 1966 are uncontroversial. Any researcher working on human subjects would make the same, and many others have before me.

    1.1 Tiny sample sizes that offer no statistical power to generalize

    It may be too small for Ed’s tastes, but there is no other physiological investigation into the body’s responses to arousal and orgasm that is near this large; 382 women and 312 men and a minimum of 7,500 complete cycles of sexual response (Masters 1966 p.12-15). I’d love a bigger study with more modern amenities, but this is the best we have, and honestly, I think calling it tiny is a bit of a stretch.

    First, the fact that there are no other larger studies is irrelevant to question of this study’s sample size and power to generalize. Statistical power is not relative, it’s an intrinsic property of a study. There are many one-off studies never replicated with a larger sample. That lack makes them less relevant, not more.

    Second, let’s review the sample sizes of the groups used by M&J in the study of orgasmic response using the measures that Trisha has named as critical and definitive of orgasm, measured pelvic-floor muscle contractions (or photos) along with the other metrics.

    M&J 1966 Sample sizes for internal physiological recording of female sexual response

    Coitus to orgasm        n = 0
    Masturbation to orgasm  n = 80-380?

    In the case of intercourse, orgasm was, in every case, inferred from self report and physiological metrics Trisha has discarded as insufficient, such as blood pressure and heart rate.

    If we consistently apply Trisha’s adamant insistence on the critical physiological measures, we must reject M&J’s conclusions about different modes of orgasm because there is no such data on coitus. A comparison requires data. This is unreasonable, and at least two others agree about this…

    Third, M&J themselves admitted openly to the absence of statistical power.

    There never has been an adequate number of study subjects available to the investigative programs. . . .the major reason for the statistically inadequate number of study subjects is the problem of insufficient research funding.  (p. 19)

    The reason n=382 isn’t adequate as a sample, is that the sample was carefully selected for convenience of the researchers. That is to say, it is the very opposite of a random sample (see also discussion at point 1.5 below). Masters and Johnson, and all social science researchers, know this very well.

    1.2 Use of sex workers as participants, which can hardly be called representative of women in general

    Not actually true – although, I don’t see this as a problem anyway. Sex workers were used as preliminary subjects, because they were available, as an investigation into how tests should be set up and run. M&J explicitly said that they did not use this population in their final analysis. … And frankly, even if they did use prostitutes, I don’t see why their physiological sexual response would be any different than any other woman or man. We all have the same parts down there (as long as no disease is present).

    It is true. A research participant is any lay person recruited to provide input or response in service of a study. It does not mean “only people about whom data was recorded for use in the final analysis”. The role of the sex workers was very important, they were used to help design protocols and measures used in the later phases. They were just as much participants as anyone else, with all the same attendant rights and status. This is common in research today, as well. For example, you may want to design a survey instrument but you need to make sure the questions you ask, their phrasing, etc.., is clear and unambiguous. You can accomplish this by fielding it against a small sample. Not to collect data, but to make sure they understand the survey properly. The data is not collected or retained, nor is any of this in the final publication other than remark that a small validity trial was performed to establish the utility of the instrument.

    M&J even call the sex workers research subjects in the text (today we use the word “participant” not “subject”): This small group [of sex workers] also served as laboratory-study subjects during the trial-and-error periods required initially to devise and to establish… (p.10-11)

    1.3 Sex in a laboratory setting probably is not representative of other settings

    Here we agree, no further comment necessary.

    The Showtime dramatization of the work of William Masters and Virginia Johnson is quite excellent.
    The Showtime dramatization of the work of William Masters and Virginia Johnson, “Masters of Sex”, is very entertaining.

    1.4 No replications

    Granted, a giant study where people are hooked up to physiologic monitors and asked to do sexual acts while the researchers measure and record has not, very unfortunately, been done since. However, …the work is fundamental and there have been many studies that replicate the measurement of arousal and orgasm in people without finding anything contradictory to what M&J found. There has even been findings that work within M&J’s, but also expand on it. For instance THIS study found some more variation in the pelvic muscle responses than did M&J (1 male who could have multiple orgasms before his ejaculation).

    It’s fair to say that further research has substantiated some findings of M&J. But my argument was not that the whole study should be considered rubbish, just that it is not authoritative and definitive about the definition and nature of orgasm. I previously cited subsequent research that contradicts and expands significantly on their work in ways critical to the scientific understanding of orgasm and female sexual response. Many elements of M&J are contentious and debated. Without replication, it can’t simply be assumed to be correct. In general, an old, non-replicated study has no particular scientific standing. It is not considered right or wrong, but unknown and therefore of highly limited usefulness to research. This is true of any study, no matter how large, no matter how physical or objective the measures.

    1.5 Participants were “WEIRD” in the Henrichian sense: of a Western, Educated, Industrialized, Rich, and Democratic society. Trisha believes the study of one culture, ours, proves things about the human species.

    Well, if Human Sexual Response was a study focused on behavior or psychology rather than physiological  reactions to arousal and orgasm then I think this would be an incredibly valid criticism. However, ladies all over the world have the same parts, just like men all over the world do. Granted, the women in other parts of the world might need to think and do different things to become aroused (this is incredibly dependent on psycho-social element), but when they do become aroused, it can be detected in their bodies just the same way we detect it in WEIRD bodies. We can also detect when they are having orgasms, just the same way we detect it in WEIRDs.

    The parts are often not the same. Comparing western and non-western small-scale societies, you tend to find that the former has: radically different levels of blood cytokines like IG-e or IL-6, male prostates 2x as large by age ~40, entirely absent bone faceting on the talas and tibia, magnitudes of order higher testosterone levels, massive differences in type and diversity of gut bacteria now implicated in everything from disease to cognition. Focusing on female sexuality, we have major effects of hormonal birth control on preferences, attitudes, sexual activity. In fact the mere reality of women having many ovulatory cycles instead of periodic pregnancy/nursing has effects on physical and mental health that we’re just starting to understand. In some places there are terrible practices like infibulation. The body aside, we know the brain and endocrine system orchestrates and causes orgasm to happen, so the psychology can’t be disregarded as an inconvenience. Orgasm is a mental event. The physical signs are only indicators that it has occurred.

    These are mostly just examples. I encourage you to read Henrich et al 2010’s paper if you haven’t. The problem is not what you can identify is wrong with your sample, it’s that you often can’t. You assume that your measure is universal, but that has turned out to be wrong, even when researchers were certain that it was a universal. M&J appreciated this point, even if Trisha does not. They refused to even try to statistically analyze the data from their intake surveys: the material returned from a total of 654 male and 619 female interviews in a selected population is too meager statistically to be of significance (p. 19, emphasis mine). 1273 is a pretty respectable sample size- unless it’s from a narrow bit of the population. The whole study, by their own admission, is a narrow slice of people skewing hard toward educated, white, middle-class, and living in a single geographic metropolitan area. They understood, as all credible researchers, that this is a fine way to begin a research program, but it is only a beginning and requires much more work with better samples to substantiate it.

    1.6 Contradictory findings (e.g. King et al. 2010): Fundamentally, these data would seem to contradict the Masters and Johnson (1965) view that masturbatory orgasms are the same as those achieved through intercourse, especially in terms of pleasure and sensation.

    This quote boldly stood out to me, back when I read this particular article, as fully inaccurate, so it’s unfortunate that it was picked to prove there is data contradicting M&J’s work. “These data” that the quote is discussing are ones that show (they thought somewhat surprisingly) that a good number of orgasms with a partner were subjectively rated lower than masturbatory orgasms by women in their study (another group of partner orgasms were rated higher, but they found that less surprising). Anyway, that’s not contradictory at all to M&J’s findings. Although M&J were clear through the study that the basic physiological elements such as spasmic release of muscle tension were universal to all orgasms, including masturbatory and those had during intercourse, they never held that they were the same in terms of pleasure or sensation.

    The quote is not inaccurate. M&J wrote,  the maximum physiologic intensity of orgasmic response subjectively reported or objectively recorded has been achieved by self-regulated mechanical or automanipulative techniques. . . .The fundamental physiology of orgasmic response remains the same [whatever the mode of stimulation] (p. 132, emphasis mine).

    The authors collected data on subjectively reported physiological responses including muscle spasms and engorgement, but they found that the type of stimulation did matter and that, per the data, the orgasms may not be all physiologically identical. Not only is this contradictory of M&J, but the paper also expands in new, important areas that M&J didn’t really touch, such as reported emotional intimacy. This paper also published multivariate statistical analysis and used validation tools. Did M&J properly characterize their observations? We have no idea. They did not publish the data. The point I am making here is not that this one paper by King et al is the superior replacement for M&J, but to illustrate that many papers, like this one, do not necessarily accord with M&J, use a more sophisticated approach, and use modern tools and ethical standards permitting real investigation to happen. In many ways, these new sources of data are far superior and do not rely on M&J methodologically or theoretically.

    Anterior vaginal sensitivity

    M&J failed to find a fact critical to their investigation. The internal anterior surface of the vagina has been documented to be more sensitive and important to female sexual response than the others (Komisaruk & Sansone,2003; Komisaruk et al.,2004). King et al. have suggested their methods may have prevented discovery of this fact because the Ulysses appliance and specula may have covered it in order to produce recordings (King et al., 2010). This, in turn, could bias their findings in favor of the supremacy of the clitoral glans.

    This failure informs about the limitations of any one study’s methods. It serves as a reminder not to take one study as gospel, no matter how objective the data recorded, because the methods constrain and partly construct the results. It is yet another reason replication and alternate methods are always required before we start calling things facts or true.

    1.7 M&J never said their physical measures were a definition of orgasm. Trisha has continually misrepresented them in this regard.

    Trisha’s references to M&J’s definition of orgasm are confused and confusing. At times she seems clear about abridging or modifying it, and other times she seems to be saying we should use their definition without qualifying it as needing amendment. For example, Trisha has written:

    Masters and Johnson’s (M&J’s) description of the physical markers of orgasm are what I believe the scientific definition of the word orgasm should be based upon.

     I think orgasm should be used to describe the M&J definition of orgasm.

    The basic description set forth by M&J is a sensible definition for orgasm

    [Ed’s] right, [ that orgasm is a mental event, an experience], but so is every other thing we humans do. It’s not useful as a definition. It’s also not a reason to disregard the M&J characterization as insufficient.

    Trisha also wrote,

    There is agreement that [orgasm] exists and about how it behaves and is measured. It is already a respected and widespread definition of orgasm. I am merely proposing it be the definition. (emphasis hers)

    So it seems like Trisha is saying there is an accepted definition based on the physiological events, and that M&J use this, along with many others, even if some lay people and perhaps researchers use other meanings. This is not correct. I explained why in my first post, but I will reiterate and expand here.

    Orgasm is a mental event. That is not just a way of looking at it, a mere aspect of it, or a way that researchers might study it… it is literally what the word refers to. The category of thing “orgasm” is, is a psychological event. Other than Trisha, nobody anywhere I know of uses any other definition. M&J don’t. Common English language does not. “Respected and widespread”? Where? By who?  Not M&J 1966. They defined female orgasm exactly one time in the book Human Sexual Response:

    For the human female, orgasm is a psychophysiological experience… (p. 127, emphasis mine)

    An experience is a purely psychological event, whether or not it has somatic correlates or causes. This is why an amputee can dream about having all of their limbs- they can have that experience whether or not it is physically real. M&J never, anywhere, defined orgasm as the sum of the measurable physiological events. They even wrote that the physiological details were “of value” only when considered in relation to behavioral theory. This would be wrong if the physiological details were orgasm in and of themselves. In the quote above where Trisha insinuates my calling “orgasm” an experience is tantamount to disregarding M&J’s “characterization” is plainly wrong. I am in full accord with M&J, who properly understood that physiological responses index or prompt the experience without actually being it. Trisha disagrees with M&J and myself.

    At a 1961/1962 conference, Masters & Johnson were asked to define female orgasm during a Q&A (Masters and Johnson, 1965):

    Dr. Phoenix: Will you repeat your definition of orgasm in the females?

    Dr. Masters: For our anatomic and physiologic purposes, if the orgasmic platform contracts, the woman is having an orgasm. The phenomenon happens in the outer third of the vagina.

    Note that Masters is careful to restrict his answer in two ways. He confines it to the anatomic and physiologic, and he says these signs mean that an orgasm is happening. That is, they indicate orgasm. They are not orgasm in and of themselves.

    In English, the word orgasm is universally defined as a psychological event, just as M&J defined it above:

    A climax of sexual excitement, characterized by feelings of pleasure centered in the genitals and (in men) experienced as an accompaniment to ejaculation.

    American Heritage
    The highest point of sexual excitement, characterized by strong feelings of pleasure and marked normally by ejaculation of semen by the male and by involuntary vaginal contractions in the female.

    The most intense point during sexual excitement, characterized by extremely pleasurable sensations and in the male accompanied by ejaculation of semen.

    The stage of sexual activity when sexual pleasure is strongest.

    Merriam Webster
    Intense or paroxysmal excitement.

    The ​moment of ​greatest ​pleasure and ​excitement in ​sexual ​activity.
    (Emphasis mine)

    Pleasure, excitement, feelings, experience. Things that do not occur in blood vessels, contractile muscles, or genitalia, but, rather, in the brain and only in the brain. Trisha’s purely physiological definition is entirely her own and bears little resemblance to the concept used by M&J, myself, social scientists, or people in general.


    Resolution Two
    Orgasm is caused by direct or indirect stimulation of the clitoral glans/vulvar area in women.

    My first argument against this resolution was that M&J themselves recorded orgasms caused by penis-vagina intercourse and by breast-touching.

    Trisha has said that M&J is the definitive work and “gold standard” on what constitutes female orgasm because of the use of objective, physiological measurements. However, she here claims we should disregard that same evidence and gives no reason why other than that it does not agree with her interpretation of what orgasm is. M&J did not expect clitoral/vulvar stimulation to be required. While they did not observe it, they wrote, orgasm resulting from fantasy also would produce the same basic physiologic response patterns, and cited 8 other papers about fantasy-to-orgasm, no Rube-Goldberg effect required (p. 132-3). She suggested that the breast-stimulation orgasms might somehow be the clitoris being stimulated by some indirect movement of muscles or something. This is wild speculation from someone who repeatedly insisted that we must only use direct, objective, physiological measurements to reach conclusions about what causes orgasm.

    At this point, I must stop. There were other points I made that Trisha replied to, but it is not necessary to continue. Trisha must concede that this resolution is unsupportable. If her own source material can be ignored in lieu of an ad hoc story without any evidence, then there is no longer any tenable expectation to be bound by that source material. If the evidence is binding, then the resolution fails. If it is not, then both resolutions fail because that is a critical basis of both.  Trisha has made these three statements:

    Masters and Johnson’s description of the physical markers of orgasm are what I believe the scientific definition of the word orgasm should be based upon.

    Orgasm is caused by direct or indirect stimulation of the clitoral glans/vulvar area in women, in the same way that orgasm is caused by direct or indirect stimulation of the penis in men.

    The M&J accounts of both the intercourse and the breast induced orgasms were observed and recorded in the lab.

    It is logically impossible for these three statements to be simultaneously correct. One must be given up.


    Both resolutions must be rejected on weight of the evidence. I have shown that my opponent’s idea of what orgasm is clearly discordant with that of William H. Masters and Virginia Johnson. Further, even were that not the case, it remains true that no credible researcher could agree a single study, no matter its features, should be held up as defining a complex human psychophysiological phenomenon. I have listed some specific flaws and limitations, to which my opponent either agreed or is unable to adequately reply. On the second resolution, Trisha has effectively conceded by admitting that her own criteria for orgasm can be ignored.

    Once again, I thank my loyal opposition for her high-minded ideals and diligent participation in this debate.


    Komisaruk, B. R., & Sansone, G. (2003). Neural pathways mediating vaginal function: The vagus nerves and spinal cord oxytocin. Scandinavian Journal of Psychology, 44, 241–250.

     Komisaruk, B. R., Whipple, B., Crawford, A., Liu, W. C., Kalnin, A., & Mosier, K. (2004). Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the vagus nerves. Brain Research, 1024, 77–88.

    King, R., Belsky, J., Mah, K., & Binik, Y. (2011). Are there different types of female orgasm?. Archives of sexual behavior, 40(5), 865-875.

    Masters, W. H., & Johnson, V. E. (1966). Human sexual response. London: Churchill.

    Masters, W. H., & Johnson, V. E. (1965). The sexual response cycles of the human male and female: Comparative anatomy and physiology. In F. A. Beach (Ed.), Sex and behavior (pp. 512–534). New York: Wiley.

    Some content edited for accuracy and clarity 10/30. Previous version available upon request.

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  • Article by: Edward Clint

    Ed Clint is an evolutionary psychologist, co-founder of Skeptic Ink, and USAF veteran.