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Ultrasound nails location of the elusive G spot
20 February 2008
From New Scientist Print Edition. Subscribe and get 4 free issues.
Linda Geddes
FOR women, it is supposed to trigger one of the most intense orgasms imaginable, with waves of pleasure spreading out across the whole body. If the "G spot orgasm" seems semi-mythical, however, that's because there has been scant evidence of its existence. Now for the first time gynaecological scans have revealed clear anatomical differences between women who claim to experience vaginal orgasms involving a G spot and those who don't. It might mean that there is a G spot, after all. What's more, a simple test could tell you if it's time to give up the hunt, or if your partner just needs to try harder.
"For the first time it is possible to determine by a simple, rapid and inexpensive method if a woman has a G spot or not," says Emmanuele Jannini at the University of L'Aquila in Italy, who carried out the research.
Jannini had already found biochemical markers relating to heightened sexual function in tissue between the vagina and urethra, where the G spot is said to be located. The markers include PDES - an enzyme that processes the nitric oxide responsible for triggering male erections (see New Scientist, 6 July 2002, p 23).
However, the team had been unable to link the presence of these markers to the ability to experience a vaginal orgasm - that is, an orgasm triggered by stimulation of the front vaginal wall without any simultaneous stimulation of the clitoris.
So Jannini's team took a different approach, and used vaginal ultrasound to scan the entire urethrovaginal space - the area of tissue between the vagina and urethra thought to house the G spot (see Diagram). The team scanned nine women who said they had vaginal orgasms and 11 who said they didn't. They found that tissue in the urethrovaginal space was thicker in the first group of women (Journal of Sexual Medicine, DOI: 10.1111/j.1743-6109.2007.00739.x). This means, says Jannini, that "women without any visible evidence of a G spot cannot have a vaginal orgasm".
Other researchers question whether what Jannini says is the G spot is a distinct structure or the internal part of the clitoris. The urethrovaginal space is rich in blood vessels, glands, muscle fibres, nerves, and - in some women - a remnant of the embryological prostate called the Skene's glands. Some researchers have suggested that the Skene's glands are involved in triggering vaginal orgasms and, more controversially, enable a small number of women to ejaculate (see "Can women ejaculate or not?").
"The authors found a thicker vaginal wall near the urethra and hypothesise this may be related to the presence of the controversial G spot," says Tim Spector at St Thomas' Hospital in London. "However, many other explanations are possible - such as the actual size of the clitoris, which, although not measured in this study - appears highly variable."
Others challenge the notion that the G spot is missing in women who don't experience orgasm. "It is an intriguing study, but it doesn't necessarily mean that women who don't experience orgasm don't have any tissue there," says Beverly Whipple at Rutger's University School of Nursing in Newark, New Jersey, whose team coined the term "G spot" in 1981.
Whipple's studies suggest that all women describe some degree of sensitivity in the area where the G spot should be. She says the next step is to ask women to stimulate themselves and then repeat the ultrasounds, as the area is believed to swell in response to physical pressure. This might reveal that all women have G spots.
Another possibility is that the women who experienced vaginal orgasms had learned to do so through practice, which has altered their anatomy, much like exercising a muscle makes it grow, says Leonore Tiefer, a psychiatrist at New York University School of Medicine. "The research would be much stronger if women without vaginal orgasm were taught how to have this experience and then repeated measurements were taken of the urethral-vaginal area," she says. "Of course this would involve teaching their partners a great deal." She would also have liked to see more extensive questioning of the women to fully understand their sexual practices.
Jannini accepts that there are limitations to his study. In particular, the small number of women he studied doesn't allow him to say what proportion of all women have G spot - although it would seem that a large number do not.
This tentative conclusion is supported by previous questionnaire-based studies such as The Hite Report, which found that 70 per cent of women do not have orgasms through intercourse, but are able to experience orgasm easily by direct clitoral stimulation.
Studies of identical and non-identical twins also support the idea that there may be physiological differences between women who do and don't experience vaginal orgasms. In 2005, Spector found that up to 45 per cent of the differences between women in their ability to reach orgasm could be explained by their genes (see New Scientist, 11 June 2005, p 6). "We know that genes are partly responsible for the variation in women's responses and this study raises the possibility that local genital differences rather than purely genetic differences in brain responses or personality may be important," says Spector.
Elisabeth Lloyd of Indiana University in Bloomington, and author of The Case of the Female Orgasm, agrees. "If Jannini's correlation does hold true, it would help explain the fact that most women do not reliably have orgasm with intercourse," she says.
Jannini is now planning larger studies to confirm his findings, and measure how many women have a G spot - if that is indeed what he has been measuring. Eventually, he says, ultrasound could be used to test whether a woman has a G spot or not.
If she does, it may even be possible to increase its size using testosterone, which both the clitoris and Skene's glands can respond to. This could increase sexual responsiveness, but could be dangerous in women with normal testosterone levels. Jannini is running a trial in post-menopausal women and those who have experienced early menopause to see if testosterone treatment can increase the size of the G spot as measured by vaginal ultrasound.
Lloyd thinks Jannini's findings could make it harder to promote the idea that women who find it difficult to orgasm are suffering from some kind of sexual dysfunction, as it suggests there are physiological differences between women. "The wide variability among women in their patterns of sexual response has made the pharmaceutical industry's challenge all the greater," she says. "If this research holds up, they would need to be very clear in marketing any product they eventually come up with."
Those women who suspect they may not have a G spot need not despair. "They can still have a normal orgasm through stimulation of the clitoris," Jannini says.
In fact, Jannini thinks his study should reassure women who have never experienced a vaginal orgasm that this is completely normal. "One clear finding is that each woman is different. This is one reason why women are so interesting."
Love - Learn more about the science behind it in our comprehensive special report.
From issue 2644 of New Scientist magazine, 20 February 2008, page 6-7
Can women ejaculate or not?
Female ejaculation is considered rare in the west, and even, by some, abnormal. In Rwanda, however, it is the norm.
Social scientists Marian Koster and Lisa Price of Wageningen University in the Netherlands interviewed 11 women and two men in Rwanda about "gukuna imishino", which is the practice of elongating the labia minora, the inner vaginal lips. "The Rwandan women and men we interviewed were clear in their opinion that all Rwandan women are able to ejaculate, the ejaculation being different from the mere squirting of urine," Koster says. "Elongated labia are seen as crucial in this respect."
From around puberty onwards, Rwandan girls start stretching the labia minora using plant extracts with antiseptic and anti-inflammatory properties, with the aim of achieving a length of about 5 centimetres. The WHO considers this practice as a form of genital mutilation, but Koster and Price argue that it should be reclassified as genital modification. "We believe that there are cultural practices that are not harmful to women's integrity and rights," says Koster.
Their interviewees reported, and Koster and Price speculate, that labial elongation increases the sexual pleasure of both sexes. "Since the labia minora swell during sexual excitement, there is a larger surface area for penile friction during coitus," they write (Culture, Health & Sexuality, DOI: 10.1080/13691050701775076).
Rowan Hooper
20 February 2008
From New Scientist Print Edition. Subscribe and get 4 free issues.
Linda Geddes
FOR women, it is supposed to trigger one of the most intense orgasms imaginable, with waves of pleasure spreading out across the whole body. If the "G spot orgasm" seems semi-mythical, however, that's because there has been scant evidence of its existence. Now for the first time gynaecological scans have revealed clear anatomical differences between women who claim to experience vaginal orgasms involving a G spot and those who don't. It might mean that there is a G spot, after all. What's more, a simple test could tell you if it's time to give up the hunt, or if your partner just needs to try harder.
"For the first time it is possible to determine by a simple, rapid and inexpensive method if a woman has a G spot or not," says Emmanuele Jannini at the University of L'Aquila in Italy, who carried out the research.
Jannini had already found biochemical markers relating to heightened sexual function in tissue between the vagina and urethra, where the G spot is said to be located. The markers include PDES - an enzyme that processes the nitric oxide responsible for triggering male erections (see New Scientist, 6 July 2002, p 23).
However, the team had been unable to link the presence of these markers to the ability to experience a vaginal orgasm - that is, an orgasm triggered by stimulation of the front vaginal wall without any simultaneous stimulation of the clitoris.
So Jannini's team took a different approach, and used vaginal ultrasound to scan the entire urethrovaginal space - the area of tissue between the vagina and urethra thought to house the G spot (see Diagram). The team scanned nine women who said they had vaginal orgasms and 11 who said they didn't. They found that tissue in the urethrovaginal space was thicker in the first group of women (Journal of Sexual Medicine, DOI: 10.1111/j.1743-6109.2007.00739.x). This means, says Jannini, that "women without any visible evidence of a G spot cannot have a vaginal orgasm".
Other researchers question whether what Jannini says is the G spot is a distinct structure or the internal part of the clitoris. The urethrovaginal space is rich in blood vessels, glands, muscle fibres, nerves, and - in some women - a remnant of the embryological prostate called the Skene's glands. Some researchers have suggested that the Skene's glands are involved in triggering vaginal orgasms and, more controversially, enable a small number of women to ejaculate (see "Can women ejaculate or not?").
"The authors found a thicker vaginal wall near the urethra and hypothesise this may be related to the presence of the controversial G spot," says Tim Spector at St Thomas' Hospital in London. "However, many other explanations are possible - such as the actual size of the clitoris, which, although not measured in this study - appears highly variable."
Others challenge the notion that the G spot is missing in women who don't experience orgasm. "It is an intriguing study, but it doesn't necessarily mean that women who don't experience orgasm don't have any tissue there," says Beverly Whipple at Rutger's University School of Nursing in Newark, New Jersey, whose team coined the term "G spot" in 1981.
Whipple's studies suggest that all women describe some degree of sensitivity in the area where the G spot should be. She says the next step is to ask women to stimulate themselves and then repeat the ultrasounds, as the area is believed to swell in response to physical pressure. This might reveal that all women have G spots.
Another possibility is that the women who experienced vaginal orgasms had learned to do so through practice, which has altered their anatomy, much like exercising a muscle makes it grow, says Leonore Tiefer, a psychiatrist at New York University School of Medicine. "The research would be much stronger if women without vaginal orgasm were taught how to have this experience and then repeated measurements were taken of the urethral-vaginal area," she says. "Of course this would involve teaching their partners a great deal." She would also have liked to see more extensive questioning of the women to fully understand their sexual practices.
Jannini accepts that there are limitations to his study. In particular, the small number of women he studied doesn't allow him to say what proportion of all women have G spot - although it would seem that a large number do not.
This tentative conclusion is supported by previous questionnaire-based studies such as The Hite Report, which found that 70 per cent of women do not have orgasms through intercourse, but are able to experience orgasm easily by direct clitoral stimulation.
Studies of identical and non-identical twins also support the idea that there may be physiological differences between women who do and don't experience vaginal orgasms. In 2005, Spector found that up to 45 per cent of the differences between women in their ability to reach orgasm could be explained by their genes (see New Scientist, 11 June 2005, p 6). "We know that genes are partly responsible for the variation in women's responses and this study raises the possibility that local genital differences rather than purely genetic differences in brain responses or personality may be important," says Spector.
Elisabeth Lloyd of Indiana University in Bloomington, and author of The Case of the Female Orgasm, agrees. "If Jannini's correlation does hold true, it would help explain the fact that most women do not reliably have orgasm with intercourse," she says.
Jannini is now planning larger studies to confirm his findings, and measure how many women have a G spot - if that is indeed what he has been measuring. Eventually, he says, ultrasound could be used to test whether a woman has a G spot or not.
If she does, it may even be possible to increase its size using testosterone, which both the clitoris and Skene's glands can respond to. This could increase sexual responsiveness, but could be dangerous in women with normal testosterone levels. Jannini is running a trial in post-menopausal women and those who have experienced early menopause to see if testosterone treatment can increase the size of the G spot as measured by vaginal ultrasound.
Lloyd thinks Jannini's findings could make it harder to promote the idea that women who find it difficult to orgasm are suffering from some kind of sexual dysfunction, as it suggests there are physiological differences between women. "The wide variability among women in their patterns of sexual response has made the pharmaceutical industry's challenge all the greater," she says. "If this research holds up, they would need to be very clear in marketing any product they eventually come up with."
Those women who suspect they may not have a G spot need not despair. "They can still have a normal orgasm through stimulation of the clitoris," Jannini says.
In fact, Jannini thinks his study should reassure women who have never experienced a vaginal orgasm that this is completely normal. "One clear finding is that each woman is different. This is one reason why women are so interesting."
Love - Learn more about the science behind it in our comprehensive special report.
From issue 2644 of New Scientist magazine, 20 February 2008, page 6-7
Can women ejaculate or not?
Female ejaculation is considered rare in the west, and even, by some, abnormal. In Rwanda, however, it is the norm.
Social scientists Marian Koster and Lisa Price of Wageningen University in the Netherlands interviewed 11 women and two men in Rwanda about "gukuna imishino", which is the practice of elongating the labia minora, the inner vaginal lips. "The Rwandan women and men we interviewed were clear in their opinion that all Rwandan women are able to ejaculate, the ejaculation being different from the mere squirting of urine," Koster says. "Elongated labia are seen as crucial in this respect."
From around puberty onwards, Rwandan girls start stretching the labia minora using plant extracts with antiseptic and anti-inflammatory properties, with the aim of achieving a length of about 5 centimetres. The WHO considers this practice as a form of genital mutilation, but Koster and Price argue that it should be reclassified as genital modification. "We believe that there are cultural practices that are not harmful to women's integrity and rights," says Koster.
Their interviewees reported, and Koster and Price speculate, that labial elongation increases the sexual pleasure of both sexes. "Since the labia minora swell during sexual excitement, there is a larger surface area for penile friction during coitus," they write (Culture, Health & Sexuality, DOI: 10.1080/13691050701775076).
Rowan Hooper
