Girls as young as nine are seeking surgery on their genitals because they are distressed by its appearance, the Victoria Derbyshire show has been told.
Dr Naomi Crouch, a leading adolescent gynaecologist, said she was concerned GPs were referring rising numbers of young girls who wanted an operation.
Labiaplasty, as the surgery is known, involves the lips of the vagina being shortened or reshaped.
The NHS says it should not be carried out on girls before they turn 18.
In 2015-16, more than 200 girls under 18 had labiaplasty on the NHS. More than 150 of the girls were under 15.
Some experts fear that pornography and images viewed through social media are leading young girls to have unrealistic perceptions of how their genitals should look.
Dr Crouch, who chairs the British Society for Paediatric and Adolescent Gynaecology, said in her work for the NHS she was yet to see a girl who needed the operation.
"Girls will sometimes come out with comments like, 'I just hate it, I just want it removed,' and for a girl to feel that way about any part of her body - especially a part that's intimate - is very upsetting."
Anna - not her real name - considered having labiaplasty from the age of 14.
"I just picked up from somewhere that it wasn't neat enough or tidy enough and I think I wanted it to be smaller.
"People around me were watching porn and I just had this idea that it should be symmetrical and not sticking out.
"I thought that was what everyone else looked like, because I hadn't seen any normal everyday [images] before then.
"I remember thinking, 'If there's surgery for it, then clearly I'm not the only one who wants this done, and maybe it won't be that big a deal.'."
She later decided not to pursue having an operation.
"I'm totally glad I didn't get it done. I didn't need it. I look totally normal. Completely and utterly normal."
Paquita de Zulueta, a GP for more than 30 years, said it was only in the past few years that girls had started coming to her with concerns over the appearance of their labia.
"I'm seeing young girls around 11, 12, 13 thinking there's something wrong with their vulva - that they're the wrong shape, the wrong size, and really expressing almost disgust.
"Their perception is that the inner lips should be invisible, almost like a Barbie, but the reality is that there is a huge variation. It's very normal for the lips to protrude."
She blames the unrealistic images girls are being exposed to through pornography and social media.
"There isn't enough education and it should start really quite young, explaining that there is a range and that - just as we all look different in our faces - we all look different down there, and that's OK."
NHS England said it did not carry out the operation for cosmetic reasons, only for clinical conditions.
For the past few years clinical commissioning groups have been able to refer only patients who are experiencing physical pain or emotional distress.
But Dr De Zulueta says some girls know they need to overstate their physical symptoms to get the surgery.
"There is awareness that they're more likely to get the operation if they say it's interfering with sex, with sport, they feel that will tick that box."
'Parallels with FGM'
Dr Crouch believes labiaplasty should be given only to girls who have a medical abnormality.
"I find it very hard to believe there are 150 girls with a medical abnormality which means they needed an operation on their labia," she said.
She added there were uncomfortable parallels between this surgery and female genital mutilation (FGM), which is illegal in the UK.
"The law says we shouldn't perform these operations on developing bodies for cultural reasons. Current Western culture is to have very small lips, tucked inside. I see this as the same thing".
Dr Gail Busby, lead adolescent gynaecologist at St Mary's Hospital, says it is important for girls and their parents to remember:
- In adolescence, the labia are still growing - with the inner lips growing first - so it is normal for them to appear prominent. Girls should not compare themselves to adult women
- By age 18, the outer lips will have grown. If girls can hold off seeking an operation until adulthood, their genitals' appearance will have changed - removing the initial reason for wanting surgery
- Surgery will probably lead to scarring and - as the labia are still developing - could lead to it becoming asymmetrical in adulthood
- Do not feel alone. Half the girls in your class will be in the same position, it is a normal part of development - it is just that no-one talks about it openly
- If parents wish to allay fears, take your daughter to a GP
- In some instances, if there are deeper concerns regarding body image, it may help to create some coping strategies
The majority of labiaplasties are done by private cosmetic surgeons on women over 18.
The industry has been criticised for normalising the procedure.
Plastic surgeon Miles Berry defended the surgery, saying it could improve women's lives.
"It can change people fundamentally, the feelings they have about themselves, their confidence and self-esteem.
"I have seen patients aged between 16 and 21 who have never had a boyfriend because they are so concerned about this."
The Royal College of Obstetricians and Gynaecologists said the operation should not be performed until a girl had finished developing, after the age of 18.
Watch the Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.