The man went to the doctor over what he thought was a stomach ache.
It turns out, he was menstruating.
Doctors at the First People's hospital in Yongkang, China confirmed the discovery after performing a CT scan and finding a uterus and ovaries in their surprised patient, named Chen.
Also discovered and removed, was a benign adrenal tumor.
"He had short hair and was dressed in man's clothes. We did not realize he was a female at first," said a doctor told the Global Times.
Doctors say Chen suffers from adrenogenital syndrome. The condition obstructs the development of genitals and affects other gender features.
There is good news for Chen, his/her ailment is treatable with hormone supplements.
Chen told doctors he has had no issues having intimate relations with his wife of ten years.
More here.