A 66-year-old man who went to the doctors with stomach ache got a shock - when he was told he was actually a WOMAN.
Stunned doctors realised the bearded patient was actually a woman when they found that the swollen belly was actually a large cyst on her ovary.
The subject suffered from two rare genetic disorders, one of which, congenital adrenal hyperplasia, increases male hormones meaning they had a beard and a "micropenis", the Hong Kong Medical Journal reported.
The other - Turner Syndrome - affects peoples X and Y chromosomes.
The patient, who grew up as an orphan, was found to have no testes, and stopped growing after puberty at the age of 10.
Seven doctors from Hong Kong where the man lived wrote in the study: "Were it not due to the huge ovarian cyst, his intriguing medical condition might never have been exposed."
The doctors said there have been only six cases where both genetic disorders have been reported in medical literature. Turner Syndrome on its own affects only one in 2,500 to 3,000 females.
The Vietnam-born Chinese patient decided to continue "perceiving himself as having a male gender with the possible need of testosterone replacement."
Most men have a X and a Y chromosome and most women have a pair of X chromosomes.
People with Turner Syndrome tend to have only one X chromosome or are missing part of their second X chromosome.