Doctors initially put her swollen stomach down to a growing tumour, however, after running tests, they discovered she was seven months pregnant.
On May 14, 1939, the little girl gave birth to a baby boy via caesarean because her pelvis was too small for her to have a natural birth.
Lina named the baby boy Gerardo after the doctor who cared for her throughout her pregnancy.
Peruvian medical professionals came up with the explanation that she suffered from ‘precocious puberty', meaning she had mature sexual organs.
It was thought that at the time that Lina was sexually abused by her father, which is what caused her pregnancy.
Her father was arrested for incest but limited evidence meant he was never charged for the crime.
Lina’s son Gerardo was raised as her brother, and only found out at the age of 10 that Lina gave birth to him.
Gerardo passed away in 1979 aged 40 from a bone disease.
Lina is still alive and had a second son with her husband, Raul. She currently lives in Lima.
This story was first published on New Idea.