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."