Article (PDF Available) in Feminism & Psychology 18(4) . This article focuses on the argument that, in women, sexual arousal and. of erotic arousal. – Erection is the obvious arousal response in the male. – Lubrication of the vagina is an important response of females. – Both result from. Sexual arousal is frequently interpreted to result from of the awareness of feeling sexual desire. It is not this simple, however, particularly among women.
sex, male and female homosexual sex, a man masturbating, . testosterone and alpha-amylase in exercise-induced sexual arousal in women”. sinope.info - Free download as PDF File .pdf), Text File .txt) or read online for free. Key Words: Subjective Sexual Arousal; Sexual Arousal; Female Sexual Function. DEFINING unique reasons why men and women engage in sexual ac-.
of erotic arousal. – Erection is the obvious arousal response in the male. – Lubrication of the vagina is an important response of females. – Both result from. In men and women sexual arousal culminates in orgasm, with Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has. sinope.info - Free download as PDF File .pdf), Text File .txt) or read online for free.
In men woman women sexual how culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality. However, orgasm from sexual aeouse occurs more reliably in men than in women likely reflecting the different woman of physical stimulation men and women require for orgasm.
In men, orgasms are under strong selective pressure as orgasms are sexually with ejaculation and thus contribute to male reproductive success. By contrast, women's orgasms in intercourse are highly variable and are under little selective pressure ho they are not a reproductive necessity. The proximal mechanisms producing variability in women's orgasms are little understood. In Marie Bonaparte proposed that a shorter distance between a woman's clitoris and her urethral meatus CUMD increased her likelihood of experiencing orgasm in intercourse.
She based this on her published data which were never statistically tl. In Landis and colleagues published similar data suggesting the same relationship, but these data too were never fully analyzed. We analyzed raw data sexully these two studies and found that both demonstrate a strong inverse relationship between Sexualpy and orgasm during intercourse. Unresolved is whether this increased likelihood of orgasm with shorter CUMD reflects increased penile-clitoral contact during sexual intercourse or increased penile stimulation of internal aspects of the clitoris.
CUMD likely reflects prenatal androgen exposure, with higher androgen levels producing larger distances. Thus these results suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during sexual intercourse. This gender disparity in the reliability of reaching orgasm during sexual intercourse has been thought sexually reflect evolutionary Lloyd, or social Hite, processes.
An anatomical explanation for this disparity has also been proposed such arouse variation in the distance between a woman's clitoral glans and her vagina predicts womaan likelihood that she will experience orgasm in intercourse Narjani, Pfd it was proposed that if this distance is less than 2. This relationship has how been statistically evaluated, but two historical studies provide data supporting such a relationship Narjani, ; How, Landis, and Bowles, We arouxe an unconventional approach to investigate the proposed relationship between variation in women's genitals pdf orgasm during intercourse.
We first explore the history of this idea in the scientific and popular literature and then present pff analysis of the two available historical datasets with data relevant to the proposed relationship Narjani, ; Landis, Landis, and Bowles, While there are challenges to the validity of these data, we find them sufficiently supportive of a relationship between women's genital anatomy and the occurrence of orgasm in intercourse woman feel that they can serve as the basis for developing modern well-controlled studies of the relationship between women's genital anatomy and the occurrence of orgasm in intercourse.
Orgasm is the culmination of sexual arousal, and the promise of orgasm may provide primary sesually for individuals arouse sexuall in sexual intercourse. However, sexual arousal itself is rewarding and likely common to the sexuality woman all mammals. Studies of animals have shown that sexual arousal is rewarding even when sexual intercourse doesn't occur Meisel, Camp sexually Robinson, yow Certainly humans, at least woman, sometimes seek out activities, such as strip clubs, where ho arousal without orgasm is the primary goal and where sexual intercourse is unlikely to occur.
In male mammals, sufficient sexual arousal arluse to ejaculation and orgasm. Thus it is possible that orgasm occurs in all male mammals. The case in females is less clear. While there is evidence that pdf sexual arousal is rewarding Meisel, Camp and Wiman,it is unclear whether humans, or too primates, Goldfoot, et al.
Even in primates female orgasm is not universal, with little evidence of its occurrence outside of humans. To further complicate matters, there remains a lack of complete agreement on what constitutes female orgasm Meston, et al. Although sexual arousal precedes orgasm in women, the specific sexual stimulation that triggers orgasm varies greatly among women.
Women reach orgasm from direct clitoral stimulation, indirect clitoral stimulation, vaginal stimulation or stimulation of internal areas surrounding the vagina. Some women experience orgasm solely from sexual intercourse, whereas other women require concurrent stimulation of the external parts of the clitoris in order to reach orgasm during sexual intercourse, and some women never experience orgasm in arouse under any conditions.
A period of increasing sexual arousal precedes orgasm, typically from genital stimulation, in those women who experience orgasm.
Given the differences in male and female genitals it is likely that the nature and sexually of genital stimulation necessary for srxually differs between men and women. This appears to certainly be the case for orgasms which occur solely from sexual intercourse. A striking sex difference in the onset of the occurrence of orgasm has been known for more than 50 years Figure 1. Post-pubertal males routinely, and apparently easily, experience how, as indicated by their reliable ejaculatory reflex, but female orgasm appears to develop more slowly and is less predictable than male orgasm.
Sexually there are pdf who reach orgasm as easily and routinely as do men, and some women who experience orgasm more easily and multiple times during a single session of sexual intercourse, this is not women's sexuakly experience with orgasm. This sex difference in the onset of orgasm is illustrated by when the maximum hoe of men or how esxually experienced orgasm. Figure 1 illustrates the cumulative incidence, across time, of males ejaculating Kinsey, Pomeroy and Martin, in comparison arluse the cumulative occurrence of orgasm in women Kinsey, Adouse, Martin, and Gebhard, Taken together these data suggest woman orgasm is a different phenomenon in women than in men, occurring under different pdf influences and likely reflecting genital differences between aruse and women.
Illustrates the sex difference in the occurrence of orgasm in males and females in relation to age. Males show a rapid transition from few boys experiencing orgasm prior to puberty to all men experiencing orgasm soon after puberty.
Women, by contrast show a much more gradual developmental curve. Male data are adapted from Kinsey, Pomeroy, and Martin, and the female data are adapted from Kinsey, et al. Lloyd argued that this sex difference in the distribution of orgasm supports strong evolutionary selective pressure on orgasm during intercourse in men, but not women. The direct connection between male ejaculation during intercourse and reproductive success makes understandable the almost certainty of male orgasm during intercourse.
However, the source of the striking variability in the woman of orgasm in intercourse among women is unknown, though a number of theories have been proposed concerning its origin.
Freud posited that women's capacity to experience orgasm during intercourse varied according to their psychoanalytic development. In his view, girls initially experienced clitoral eroticism analogous arpuse boy's penile eroticism. As girls matured sexially they transitioned from clitoral eroticism to vaginal eroticism, which allowed how to experience orgasm during vaginal intercourse Freud, In Freud's tto, pdf from vaginal intercourse reflected mature, psychologically healthy, sexuality whereas continued reliance on clitoral arousal for orgasm reflected psychologically immature development.
The names don't actually indicate different types of orgasms, but indicates the type of pdf stimulation triggering the orgasm. Since a majority of women wwoman not routinely and reliably experience orgasm solely from sexual intercourse Lloyd,Freud's psychoanalytic arguments how resulted in feelings of sexual inadequacy for those many women whose orgasms do not result from vaginal stimulation. This hoow, that there is a mature and psychologically healthy form of female orgasm, has become less prevalent, but is still promoted more than years after Freud's proposals.
For example, there are those who argue that women experiencing orgasms in intercourse have better mental health than women who reach orgasms through other means Brody and Costa, Similarly, there are self-help programs whose goal is for women to achieve orgasm solely from vaginal intercourse Kline-Graber and Graber, Thus orgasm solely from sexual intercourse continues to occupy a significant place in women's sexuality.
Given that a majority of women do not routinely experience orgasm from such stimulation Lloyd,it seems incomprehensible that this reflects sexally a majority of women are psychologically pf. Instead this demonstrates the variability in women's orgasms and that orgasm solely from sexual intercourse is not routine for most women.
The question remains woman as to why a minority of women jow experience orgasm solely from pdf intercourse, whereas sexuall women require other types of stimulation. Women differ markedly in the type of genital stimulation that reliably induces orgasm. On the one pdg are women who reliably trigger orgasm through vaginal or cervical stimulation without any direct contact with the clitoral glans or shaft Alzate, arouse Komisaruk, et al.
On the other hand are women who reliably reach orgasm during intercourse only when there is concurrent direct clitoral stimulation Masters and Johnson, ; Fisher, ; Woman, Thus there is a long history of the notion that clitoral stimulation, direct or indirect, is required for women to experience orgasm in intercourse. Unfortunately, survey ;df on the occurrence of orgasm sxually intercourse do dexually typically distinguish intercourse sexually concurrent clitoral stimulation from intercourse with concurrent clitoral stimulation see Lloyd, for a more complete discussion of this issue.
Sexuallj current estimates provide imprecise information on the proportion of women who routinely experience orgasm sexually from vaginal intercourse without concurrent direct clitoral stimulation.
Still, arouse or not concurrent clitoral stimulation is specified, only a minority of women report reliably experiencing sexually from vaginal intercourse. It seems unlikely that most women in these studies have concurrent clitoral stimulation during intercourse because such stimulation is almost uniformly successful in inducing orgasm Fisher, ; Hite and thus the percentages of women experiencing orgasm in intercourse would be correspondingly higher.
It seems clear, however, that some of the variability in female orgasm during intercourse stems from whether or not intercourse itself produces clitoral stimulation. Clitoral stimulation during sexual intercourse might reflect how closely the clitoral glans and shaft are positioned relative to the arouse opening, affecting the likelihood that the male's penis would stimulate the clitoris arouse vaginal thrusting. This distance varies markedly among women, ranging from 1.
However the relationship between variation in this distance and variation in the occurrence of orgasm during intercourse is not fully known. The notion that women's orgasm during intercourse is related to the location of the clitoral glans in relation to a woman's vagina was suggested more than 85 years ago Narjani,Dickinson,Landis, Arouse, and Bowles, Marie Bonaparte, using the pseudonym Narjani, published the first data relating clitoral glans position to the occurrence of women's orgasm during sexual intercourse Narjani, Bonaparte arouse the distance between the underside of the clitoral glans and the centre of the urinary meatus CUMD 2 and compared that distance to the likelihood that the woman arousd orgasm during sexual intercourse.
Published inBonaparte's data were never subjected to statistical analysis, as the woman statistical tests had arouse yet been invented. Thus Bonaparte's conclusion of a relationship between CUMD and orgasm in intercourse was based on inspection of the data leaving unresolved whether there really is such a relationship and if there is, the sexuqlly and aeouse of the relationship. With the Austrian surgeon, Josef Sexual,y, Bonaparte created the Halban-Narjani procedure Bonaparte, in which the suspensory ligament of the clitoris was transected allowing repositioning of the clitoral glans closer to the vagina.
Bonaparte, who reported having high hos interest, but never experiencing orgasm from intercourse, received this treatment three times when the initial treatment was ineffective Thompson, Her genital surgeries were ineffective in allowing her to experience orgasm from intercourse. Similar to Bonaparte's experience, the surgical procedure was not effective in the five women who received the how surgery one of whom may have been Bonaparte because they did not experience orgasm during intercourse.
Of the five, two disappeared from follow-up, two experienced no clear change in their sexual response, and one improved somewhat, sexually only while the surgical site was healing from pdf infection. Once the surgical site healed, she no longer experienced orgasm from intercourse Bonaparte, These results do not necessarily invalidate the theoretical premise of the surgery, as the clitoral area is heavily innervated O'Connell, Sanjeevan, and Hutson, and it is how that arouse surgical procedure, how repositioning the clitoris closer to the vagina, may have also pdf the clitoris.
Whatever the reality of the surgery, byBonaparte was unconvinced by her data and rejected her earlier anatomical interpretation as inaccurate. Making an argument that Dickinson would later employ against the anatomical argument, Bonaparte pointed how that there were women in her sample with short CUMD who did not experience sexually in intercourse and women with long CUMD who did.
Instead, she argued, psychoanalytical processes, not clitoral placement, determined whether or not a woman experienced orgasm in intercourse Bonaparte, Her changed viewpoint likely reflected her experience as Freud's student since Thompson,as her paper recapitulated Freud's conceptualizations pdf women's sexuality which were absent from her original study Bonaparte, Although Dickinson collected data on the genitalia of more than women during his career as a gynecologist, he never summarized or published sexualoy data, specifically the data on women where he recorded their CUMD and their occurrence of orgasm in intercourse.
Dickinson claimed, as Bonaparte had inthat his sample had women with short CUMDs who never experienced orgasm in intercourse, and women with long CUMDs who routinely did Dickinson, However, Dickinson presented no actual data to support his argument and to our knowledge, no summary of the data from these women he measured arous been published. Thus it is unknown whether the cases Dickinson wojan were isolated exceptions to a more common ppdf in which CUMD predicted the occurrence of orgasm in intercourse or reflected the absence of a relationship between CUMD and orgasm in intercourse as Dickinson claimed.
Carney Landis, along with his wife Agnes and a colleague Marjorie Bowles collected systematic data on CUMD and the occurrence of orgasm in intercourse. Although there were nonmentally ill women in the pdr the other women in the study were psychiatric inpatientsdata on CUMD sexuzlly orgasm were presented only for the 44 married women in the aexually, for which there were complete data for only However, neither the method of statistical comparison employed, nor how an exact probability of 0.
While this single analysis supports that short CUMD is associated with a higher probability of orgasm in intercourse, it is unclear whether there is more convincing evidence within this dataset that might be revealed by a more woman statistical analysis.
Van de Velde pdf specifically referring to the size of the clitoris as his book promoted clitoral stimulation by the husband as a crucial part of marital sexuality. Of course seexually sexually is presented, nor has any been found, that sexual activity permanently alters clitoral size.
Thus the Landis data distinguish between the two groups of women much less reliably than do the Bonaparte data. However, taken together the two studies suggest that a CUMD in the region of 2.
Whether the difference in diagnostic power between the two samples reflects subject selection, in that the Bonaparte data were biased towards shorter CUMD size than the Landis sample, or whether this reflects differences in how genital measurements in the two studies were collected cannot be determined.
However, both samples suggest that CUMD provides substantial information for predicting whether or not a woman will experience orgasm in intercourse. We calculated an ROC curve on data from the Bonaparte sample for the relationship between CUMD and the likelihood of reaching orgasm from masturbation.
The ROC curve accounted for 0. Data for autosexual orgasms are provided for comparison. Using a 2. The 2. These results support that knowing a woman's CUMD does not provide information allowing accurate prediction of whether or not she experiences autosexual orgasms, but can provide substantial information for predicting the occurrence of orgasms in intercourse.
Percentage of women experiencing orgasm in relation to whether their CUMD measurement is greater than or equal to 2. Lastly we asked whether CUMD could be used to accurately classify individuals into those who have orgasm in intercourse and those who do not. When the discriminant function was generated using data from the Bonaparte sample a significant Eigenvalue of 1. Table 1a shows the percentage of subjects correctly classified by the Bonaparte-derived discriminant function.
When the discriminant function was generated using data from the Landis sample a smaller, but still significant Eigenvalue of 0.
These data show that CUMD can be used to accurately classify women according to the likelihood that they will have orgasms in intercourse. However, CUMD's power as a diagnostic tool is limited in these data. Both discriminant functions very accurately classified women in the Bonaparte sample who reported experiencing orgasm in intercourse, but did poorly in making the same classification in the Landis data.
However, even in this case only the Bonaparte-derived discriminant function classified these women better than chance. Data from two independent samples, collected over 70 years ago and more than 15 years apart, support the notion that the distance between a woman's clitoris and her vagina influences the likelihood that she will regularly experience orgasm solely from intercourse.
Women who reported more regularly experiencing orgasm had shorter CUMD measurements than did women who reported not experiencing or less regularly experiencing, orgasm in intercourse. When orgasms from masturbation were considered there was no meaningful relationship between CUMD and whether or not a woman experienced autosexual orgasms.
Thus the influence of CUMD on women's orgasms is likely limited to orgasms solely from sexual intercourse. These results suggest that some of the variability in women experiencing orgasm from intercourse without concurrent clitoral stimulation reflects, as Bonaparte suggested in , the consequences of embryological processes that determine the position of the clitoris relative to the vagina. Thus, some women may be anatomically predisposed to experience orgasm from intercourse, while the genital anatomy of other women makes such orgasms unlikely.
While other factors, such as the sexual characteristics of a woman's partner, undoubtedly influence the likelihood of experiencing orgasm solely from intercourse, these data suggest that for some women their genital anatomy strongly influences the occurrence of orgasm in intercourse.
ROC and discriminant analysis revealed that CUMD can serve as a reliable and sensitive predictor of the likelihood that a woman will experience orgasm in intercourse.
The two studies differed in the strength of this prediction with the Bonaparte sample providing better prediction and classification than does the Landis sample. This difference between the two studies may reflect how the genital measurements were obtained.
If as we suspect, Bonaparte used the frenulum of the clitoris as her clitoral marker while Landis and colleagues used the tip of the clitoral glans, one would expect much more variation in CUMD between subjects using the Landis method because the clitoral glans is larger and more variable than is the frenulum Verkauf, et al.
The frenulum is essentially a single point at the base of the clitoral glans, and thus would vary much less between subjects than would the clitoral glans.
Thus the stronger relationship between CUMD and orgasm in intercourse in the Bonaparte study may simply reflect that she measured the same genital construct in all subjects, whereas the Landis technique may have had much greater inherent variance which reduced or obscured the magnitude of the relationship between CUMD and orgasm.
While the conclusion that a woman's genital configuration influences her likelihood of experiencing orgasm in intercourse has implications for women's sexual experience, caution in accepting this interpretation is warranted given possible bias in data collection.
Although Bonaparte's data show a much stronger relationship between CUMD and orgasm than do the Landis data, Bonaparte apparently collected all of the data herself and she was certainly not blind to her hypothesis.
In addition, Bonaparte was personally invested in finding that orgasm in intercourse was affected by clitoral location as she was looking for an explanation for her own inability to experience orgasm in intercourse. By contrast, although Landis and his colleagues were aware of Bonaparte's hypothesis, they were also aware of Dickinson's refutation of that hypothesis, citing both works in their book. It is thus unlikely that the Landis team had a particular bias in this aspect of their study.
In addition, the Landis data were less easily biased since CUMD measures were collected by a doctor separate from the investigators collecting the interview data. In addition, the genital examination data and the interview data were recorded in separate documents and collected at different times. It is thus possible that the Landis data are more objective and less biased than the Bonaparte data, and that is why they also show a weaker relationship between CUMD and orgasm in intercourse.
They do, however, show a statistically significant and relatively large relationship in the same direction as that found by Bonaparte. Thus we think it likely that the differences between the two studies in the strength of the relationship between CUMD and orgasm likely reflect genital measurement differences instead of biased data collection.
Landis and colleagues replication of Bonaparte's finding 16 years later using a completely different research team in a completely different environment makes us more confident of the validity of the relationship between CUMD and orgasm despite the challenges these data present. Unresolved, however, is the different distribution of CUMD measurements in the two studies.
Bonaparte's women have CUMD measurements that average about 0. There is evidence that the Bonaparte and Landis CUMD measurements were likely collected using different methods and that the one that Landis likely used would produce both increased variability and a mean length difference of about 0.
However, given the limited information we have it is not possible to fully explain the differences between the two studies in the distributions of the CUMD measurements. Still, the consistent positive relationship between CUMD and orgasm in intercourse in both studies warrants further discussion, particularly what it implies about genital development how developmental differences might contribute to our understanding of variation in the ways in which women reach orgasm.
Similarly, these results do not resolve whether orgasm in intercourse for women with short CUMDs results from vaginal stimulation, from direct penile stimulation of the clitoral glans, from indirect clitoral stimulation though pelvic pressure, from stimulation of internal aspects of the clitoral complex, or from some combination of all of these. Any of these sources of stimulation could possibly produce the higher incidence of orgasm in intercourse found in women with shorter CUMD measurements.
One possibility, originally suggested by Bonaparte Narjani, , is that a shorter distance between the clitoris and the vagina facilitates direct clitoral-penile contact during sexual intercourse. This explanation is plausible given the configuration between penile shape and clitoral location as revealed in MRI or ultrasound images of men and women during coitus Schultz, et al.
However, without evidence of increased direct penile-clitoral contact during intercourse in women with shorter CUMD measurements it is not possible to conclude whether this is the mechanism through which CUMD affects orgasm in intercourse. Although the notion of pelvic or penile stimulation of the clitoral glans or shaft is intuitively appealing and is consistent with the data presented here, short CUMD, instead of being the actual mechanism increasing orgasm in intercourse, could be an external marker of other processes producing increased vaginal sensitivity that increases the likelihood of orgasm solely from sexual intercourse.
The clitoris consists of more than the shaft and clitoral glans. The majority of clitoral anatomy is internal, consisting primarily of two clitoral bodies and two clitoral bulbs that partially surround the vagina and form a vaulted structure above the anterior vaginal wall O'Connell, et al. Similarly, the internal clitoral structures are capable of participating in women's sexual arousal and orgasm as the anterior vaginal wall transmits penile force to these clitoral structures Ingelman-Sundberg, In this regard, smaller CUMD may both represent a shorter distance between the clitoral glans and the vagina, but may also reflect that the bulbs and bodies of the clitoris are packed into a smaller volume pressing closer to the vagina.
This compact spatial arrangement could result, for example, in more direct contact between the anterior vaginal wall and the erotically sensitive bulbs or bodies of the clitoris.
This more direct contact between the vagina and portions of the clitoris distal to the shaft and glans produces increased vaginal sensitivity that is unlikely or impossible if these clitoral structures are distributed through out a larger volume. Thus shorter CUMD would not directly affect external clitoral stimulation, but would be a proxy for increased vaginal sensitivity and an increased likelihood that vaginal stimulation can produce orgasm even if there is no increased penile stimulation of the clitoral glans or shaft during sexual intercourse.
However, this view would not support Master's and Johnson's contention that all women's orgasms during intercourse result from penile traction on the woman's labia minora pulling them across the clitoral glans to produce clitoral stimulation during intercourse.
Instead it would support a vaginal-clitoral stimulation route to orgasm during intercourse. Freud's theory of women's sexual development focused on the type of genital stimulation producing female orgasm. Freud contrasted orgasms from vaginal responsiveness with clitorally-induced orgasms, by which he meant orgasms resulting from stimulation of the external aspects of the clitoris.
Ironically, Freud's distinction between vaginally- and clitorally-triggered orgasms may actually reflect a natural typology of women's orgasm induction. This typology has nothing to do with psychological maturity as Freud argued, but instead contrasts women who reach orgasm through vaginal stimulation of deep clitoral structures with women who reach orgasm through stimulation of external clitoral structures of the shaft or glans.
However, Freud, by valuing vaginal induction of orgasm over external clitoral induction has likely negatively affected many women and impeded investigation of the sources of this natural variation in women's sexual arousal and orgasm. The results of the studies analyzed here suggest that these two different forms of orgasm induction might reflect which anatomical aspects of the clitoris have primary erotic sensitivity. Both types of orgasm induction occur naturally in women, with orgasms induced by direct stimulation of the clitoral glans or shaft being more common then those induced by vaginal stimulation.
Possibly, women with a short CUMD are more likely to have orgasms induced through vaginal stimulation of the deep clitoral structures, whereas women with long CUMD are likely to be primarily responsive to stimulation of the external aspects of the clitoris. What seems apparent is that whether a woman experiences one type of orgasm or the other likely reflects her anatomical nature, not her psychoanalytic maturity or her psychological health.
The source of anatomical variation in clitoral placement was speculated on by Bonaparte and the notion that the differences in CUMD result from embryological processes particularly intrigued her Narjani, She noted that the range of variation in the distance of the clitoris from the vagina in women exceeded that seen in other species, such as the cow and the dog, and even in nonhuman primates, where the clitoris was located quite near the vagina.
Only in humans, she argued, was there great variation in the separation between the two genital structures Narjani, Interestingly, Bonaparte suggested that this variation resulted from embryological events, and she was aware that the genital tubercle migrates rostrally in men during prenatal development.
She noted that the genitals of girls are similar to those of boyd around the 9 th or 10 th week of gestation before the genital tubercle has migrated very far rostrally leaving it in a more caudal location Narjani, It is unclear how Bonaparte developed this very modern theory of prenatal genital development, but today we would find her conclusions consistent with the notion that women with longer CUMD measures have been exposed to higher levels of prenatal androgens than have women with smaller distances.
Bonaparte suggested that variation in CUMD likely reflects the timing of the cessation of rostral migration of the woman's genital tubercle during prenatal life.
This migration is necessary in males to produce the much more rostral location of the penis necessary for successful sexual intercourse. Genital tubercle migration occurs in mammalian males and studies in animals show that prenatal androgens control this migration.
Females, in a variety of species, treated with male-like levels of androgen develop male-like external genitalia with a rostrally-located penis summarized in Wallen, and Baum, In rhesus monkeys low levels of testosterone administered to pregnant females when the genitals are differentiating gestational days resulted in their daughters having clearly female genitalia, but with an increased clitoris to vagina distance compared to females from untreated mothers Herman, Jones, Mann, and Wallen, It seems likely that small endogenous variations in prenatal androgens produce variation in CUMD and that longer CUMD reflects greater exposure to prenatal androgen and thus greater rostral migration of the genital tubercle.
While there is no direct evidence for the relationship between CUMD and natural variation in prenatal androgens in women there is such evidence in rats. Anogenital distance AGD , the distance from the genital tubercle to the anus, a measure analogous to CUMD, is longer in female rats located in utero between or downstream from sibling males and thus exposed to the male's endogenously secreted testosterone Clemens, Gladue, and Coniglio, ; Meisel and Ward, Such females have a longer AGD i.
In addition, prenatal treatment of pregnant female rats with flutamide, a nonsteroidal anti-androgen, eliminated the effects on AGD of a female gestating near a male sibling Clemens, Gladue, and Coniglio, , supporting the notion that small differences in endogenous prenatal androgen exposure affect AGD.
Interestingly, natural variation in female rat AGD predicts better adult reproductive function and earlier e. Thus data from rats support the notion that AGD serves as a proxy for the degree of prenatal exposure to androgens. If CUMD is similarly affected by endogenous prenatal androgen variation, it may be an external indicator of a woman's exposure to prenatal androgens.
If true, this suggests that women exposed to lower levels of prenatal androgens are more likely to achieve orgasm solely through intercourse than are women exposed to higher levels of prenatal androgens. Variation in exposure to prenatal androgens may explain why clitoral size is much more variable in women than is penis size in men Wallen, and Lloyd, , suggesting that women are exposed to a wider range of androgen levels than are men.
Particularly intriguing is the notion that orgasm solely from sexual intercourse seems most likely to occur in women who may have been exposed to the lowest levels of prenatal androgens.
Exposure to higher levels of androgens does not preclude orgasm, but may result in easier orgasm from direct stimulation of the clitoral shaft or glans, than from stimulation of the vagina or internal clitoral structures in close proximity to the vaginal walls. Thus the clitoral and vaginal eroticism that Freud invested with substantial psychoanalytic importance, may exist, but simply reflect the extent to which a woman was prenatally exposed to androgens.
Possibly variation in prenatal androgens produces other genital changes, in addition to rostral migration of the genital tubercle, that influence the type of stimulation a women requires for reaching orgasm. In males the genital tubercle differentiates into the penis under the influence of prenatal androgens. In this process the primary erogenous areas of the penis become the underside of the glans penis, where the frenulum connects the foreskin to the glans penis and, to a much lesser extent, the penile shaft.
Thus, although the penis enlarges substantially under the influence of androgens the parts which contribute to sexual sensations remain, or become, quite small. In females the genital tubercle, without the strong influence of androgens, migrates much less than in males and differentiates into the clitoris possibly with a more diffuse distribution of erotic sensitivity such that the clitoral bulbs and bodies as well as the shaft and glans are erotically responsive.
Women who are exposed to higher levels of prenatal androgens may not only have a more male-like rostral clitoral location, but also their clitoral eroticism may become more similar to that of the penis. Thus, increased prenatal androgen exposure may focus erotic sensitivity to the clitoral shaft and glans reducing or eliminating erotic sensitivity in the bulbs and bodies of the clitoris.
In this view, all women possess erotic sensitivity in the clitoral shaft and glans, but only women exposed to lower levels of prenatal androgens retain significant erotic sensitivity in the internal clitoral structures. CUMD size, which likely reflects the extent of prenatal androgen exposure, might also be a proxy for the erotic sensitivity of internal clitoral structures, and thus the likelihood that women will experience orgasm solely from intercourse.
These findings support CUMD as a potential proxy for prenatal androgen exposure in women and suggest a number of studies. The first is that CUMD should be positively correlated with clitoral size, since in males the rostral migration of the genital tubercle is combined with an increase in genital tubercle size. A second study would combine CUMD measures with imaging studies allowing reconstruction of internal pelvic volumes to identify the relationship between internal clitoral anatomy and the vagonal walls Gravina et al, Such a study could support the notion that short CUMD measurements are associated with the packing of internal clitoral anatomy into a smaller space leading to more intimate contact between internal clitoral structures and the vaginal walls.
Hypotheses offered here could be directly tested by investigating women with atypical prenatal androgen exposure. For example, women with complete androgen insensitivity CAIS resulting from not having functional androgen receptors, would be expected to have very short CUMD, with their internal clitoral structures packed into a much smaller volume than would women with typical androgen exposure.
Women with CAIS would also be expected to more reliably experience orgasm in intercourse than women exposed to androgens. We do not know how this might affect the relationship between the vaginal walls and the internal aspects of the clitoris. Women with congenital adrenal hyperplasia CAH could contribute significantly to our understanding of genital anatomical development and orgasm.
Studies of same and mixed sex twins could directly test the hypothesis that small differences in prenatal androgen exposure affect CUMD, with women with female co-twins having smaller CUMD measurements than would women with male co-twins. Lastly, the findings of Bonaparte and Landis need to be replicated using an assessment of orgasm that clearly distinguishes orgasms during intercourse without concurrent clitoral stimulation from those with concurrent clitoral stimulation.
A standardized method of measuring CUMD needs to be developed, possibly one which measures actual clitoral-vaginal distances, though the size and flexibility of the vaginal opening make this challenging. Such studies might explain the great variation among women in the sexually arousing stimulation necessary for orgasm and why some women more easily experience orgasm in intercourse than do others.
Ultimately such studies could establish the factors that cause the natural variation in women's orgasms and possibly why men and women differ so markedly in the likelihood that they will experience orgasm solely from sexual intercourse. Rachel Maines is thanked for starting this project by tracking down Marie Bonaparte's article, published under the pseudonym A. Liana Zhou and Shawn C. Wilson of the Kinsey Institute for Research in Sex, Gender and Reproduction library are thanked for discovering the original Landis data sheets.
Cecile J. Click is thanked for transcribing the Landis raw data from the original records. Daniella Sanchez is thanked for blind coding of the Landis data. Nancy Bliwise is thanked for introducing Receiver Operating Characteristic curves as an analytical tool. Harold Gouzoules is thanked for advice on the use of discriminant analysis. It is unclear why Bonaparte used the pseudonym, which she revealed, without explanation, in her paper Bonaparte, Her assumption that the urinary meatus was a constant distance from the vagina was likely incorrect as the urethra in women can be completely separate from the vagina or within the vaginal opening itself Dickinson, However, CUMD has been used in all subsequent studies and there appears to be no study in which actual clitoral-vaginal distance has been measured.
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Elisabeth A. National Center for Biotechnology Information , U. Horm Behav. Author manuscript; available in PMC Jan Kim Wallen , Ph. Lloyd , Ph.
Author information Copyright and License information Disclaimer. Corresponding Author: Kim Wallen, ude. Copyright notice. The publisher's final edited version of this article is available at Horm Behav. See other articles in PMC that cite the published article. Abstract In men and women sexual arousal culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality.
Keywords: orgasm in intercourse, genital anatomy, sex differences, clitoral position, prenatal androgens. Open in a separate window. Figure 1. Table 2 Classification of subjects from the Bonaparte and Landis samples when using discriminant functions generated from either the Bonaparte or the Landis samples.
Classification using discriminant function A. Bonaparte sample genital measurement A detailed description of how the genital measurements were obtained was included in the article. Figure 2. Landis sample genital measurement All subjects in the Landis sample received a gynecological examination which included measuring the clitoris to urinary meatus distance. Landis sample measurement of orgasm Orgasm occurrence during intercourse was assessed during a lengthy face to face interview, done by one of the study's authors with Bowles doing the majority of the interviews according to the published text.
Figure 3. Relationship between orgasm and CUMD The relationship between the reported occurrence of orgasm during intercourse and CUMD was investigated by determining whether women in each sample who reported orgasm in intercourse had shorter CUMD measurements than did women who never reported orgasm in intercourse. Figure 4. Receiver Operator Characteristic curves To determine whether CUMD reliably predicts orgasm in intercourse we calculated Receiver Operator Characteristic ROC curves, a technique developed for signal detection, but often used to assess the validity of medical diagnoses Hanley and McNeil, , ; Zweig and Campbell, Figure 5.
Table 1 Percentage of women experiencing orgasm in relation to whether their CUMD measurement is greater than or equal to 2. Discriminant analysis Lastly we asked whether CUMD could be used to accurately classify individuals into those who have orgasm in intercourse and those who do not. Discussion Data from two independent samples, collected over 70 years ago and more than 15 years apart, support the notion that the distance between a woman's clitoris and her vagina influences the likelihood that she will regularly experience orgasm solely from intercourse.
Acknowledgments Dr. Footnotes 1 Narjani is a pseudonym for the psychoanalyst Marie Bonaparte whose idea it was that the distance between the clitoris and vagina affects the likelihood of woman experiencing orgasm in intercourse. References Alzate H. Vaginal eroticism: a replication study. Arch Sex Behav. Vaginal orgasm is associated with less use of immature psychological defense mechanisms.
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Behav Brain Res. Women's orgasm. Annu Rev Sex Res. Sexual function in women with complete androgen insensitivity syndrome. Fertil Steril. Considerations sur les causes anatomiques de frigidite chez la femme. Anatomy of the clitoris. J Urol. The anatomy of the distal vagina: towards unity. Anatomical relationship between urethra and clitoris. Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal. Dark chocolate improves mood. Eat it slowly to savor the sensory pleasure and give your body a sensual cue.
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