Labiaplasty - an operation to reduce one or both of the labia minora, or inner lips of the vagina - is rapidly gaining popularity as women go under the knife for health-related or purely cosmetic reasons. In the West, the rise in the operation's popularity is startling. In Britain, for example, there's been a five-fold increase in the past five years to more than 2,000 surgeries in 2011 in the public health system alone; while American women spent US$6.8 million on the procedure in 2009, according to the American Society for Aesthetic Plastic Surgery. It's increasingly common in Asia, too, with the cosmetic surgery hot spot of Thailand catering to a growing number of women from around the region - including plenty from Hong Kong. Part of the trend for so-called "designer vaginas" - other popular types of cosmetic vaginal surgery include vaginal rejuvenation or tightening, hymenoplasty ("revirgination") and clitoral unhooding - labiaplasty is a fairly straightforward surgical procedure, using a scalpel or laser. It can be performed either under local or general anaesthetic, takes about 20 minutes and rarely goes wrong. Still, it is not the type of operation that any woman would take lightly. So why are so many women willing to undertake the surgery when many doctors question whether, in most cases, it's necessary, or even advisable, for them to do so? In this type of surgery, there is no clear dividing line between what is necessary and what isn't. Overly large labia can be present from birth, but can also be caused or exacerbated by medical conditions, and by the stresses and strains of childbirth, sex, masturbation and even genital piercings. Some women opt for labiaplasty because the size of one or both of their labia is causing them discomfort, or even pain, usually during sex or while undertaking strenuous seated activities such as cycling, but in some cases all the time. Other women are just unhappy with the appearance of their vagina and want to change it. The problem is there's no definition of a "normal" vagina. There is no set of dimensions women and their doctors can use to determine whether labia are abnormally large. The term labial hypertrophy describes the labia minora extending beyond the labia majora, but that's quite common and may not be a problem in itself. That has led to concerns that women are opting for the procedure to conform to an unrealistic notion of what the female genitalia should look like. It is the ultimate area in which women are being asked to live up to an ideal of beauty. The American Congress of Obstetricians and Gynaecologists says labiaplasty is unnecessary, and possibly unsafe and unethical. Women are becoming more aware of how their body looks down there and are empowered by information Vitasna Ketglang, director, Cosmetic Gynaecology Centre, Thailand Clinical guidelines state that, in addition to women with any form of gynaecological disease and smokers, the surgery is inadvisable for women with unrealistic body-image goals - but realism in this case is entirely subjective and at least partly culturally defined. The divide between functional and aesthetic motivations for the surgery is reflected in confusion over which medical discipline performs it. In Thailand, as in many countries, most labiaplasties are undertaken by cosmetic surgeons, but in United States, for example, gynaecologists commonly perform it - largely because they're trying to muscle in on the lucrative cosmetic surgery market. The procedure isn't cheap - costing between HK$8,000 and HK$20,000 in Thailand - and so, as with all cosmetic surgery, doctors have an incentive to recommend it. In reality, however, a lot of women who undertake the procedure don't need medical prompting. Jenny (whose name has been changed for reasons of patient confidentiality), 29, from Sydney, was thinking about having the operation for at least a decade before she travelled to Bangkok's Yanhee International Hospital 18 months ago. "I've never liked the appearance of my genitalia," she says. "As a teenager I always felt embarrassed about the way my vagina looked and felt that I was abnormal. I had quite long labia minora with a large asymmetry [of more than 2.5cm] between the length of each side. In particular, I felt uncomfortable to wear small underwear because I would find that my lips might protrude. I often felt embarrassed if I was with a new partner and didn't feel I was sexy. I also found that the lip that protruded could become itchy or irritated from being exposed and was often uncomfortable." In fact, she adds, the operation didn't feel like a risk at all: "I really disliked the appearance so figured it couldn't be much worse." She says that the operation itself was a good experience, although she was in pain and swollen afterwards, with an intense itching and burning sensation that lasted several weeks. She adds that she was advised not to have sex for six to eight weeks afterwards, but that it was actually more like four months. The result, however, she says, "is perfect. It looks totally natural. I am much more confident in myself as a woman and am also more comfortable physically." The doctor who performed Jenny's operation was director of the Cosmetic Gynaecology Centre at Yanhee International Hospital, where about 50 labiaplasties are performed a month, and the chair of the Thai Cosmetic Gynaecology Society. She says that labiaplasty has become more popular in recent years because before, "a woman who had not heard about the surgery may possibly have felt insecure about her enlarged labia, but would not do anything about it, and may have considered having an elongated labia minora her 'normal' anatomy. "Women are becoming more aware of how their body looks down there and are empowered by information. The adult media and the internet may be important tools in disseminating information about the labiaplasty procedure." As Professor Somyos Kunachak of Bangkok's Yoskarn Clinic says, "This is not a new procedure: we have been performing it for more than 20 years." He adds that most women who have "unsightly" labia - a subjective judgment, of course - want them corrected, but "in the past, they just didn't know that this area could be beautified and may have been a bit shy to request it". He says that almost all his patients, who include a number from Hong Kong, have the operation for aesthetic reasons, and about half also have vaginal rejuvenation at the same time. Vitasna, who has also had many patients from Hong Kong, says women come to her for a mixture of aesthetic and functional reasons. She acknowledges that the operation can pose ethical questions. "I am an advocate of women's rights and I believe in respecting a woman's autonomy or freedom: women have the right to choose to change their bodies however they like," she says "It is, however, important to determine the motivation for surgery. "Surgery is just an option. It takes great courage for some women to accept having elongated, large labia. They think it is not normal. Acceptance and surgery are both options women need to weigh." According to Jano Ha, spokesperson for Kamol Cosmetic Hospital in Bangkok, which is headed by leading aesthetic surgeon Kamol Pansritum, the operation can have a helpful psychological effect. "We have found that many people have had mental problems because of a little part of their body that they did not like. Plastic surgery can help them to fix those parts and so to improve their mental state." Cosmetic surgery often provokes strong opinions, and surgical genital alteration, of course, is always an emotive subject. Labiaplasty might sound a drastic move, but an increasing number of women feel they need it. That could just be because more women have heard about it, but it could also be because more want it, for whatever reason. As ever with cosmetic surgery, the line between correcting an abnormality and trying to conform to a physical ideal is often blurred.