Adolf Hitler's medical records from a 1923 examination by a prison doctor revealed that the dictator was suffering from a condition known as cryptorchidism, which left him with one undescended testicle. Although the condition would not have affected his health or sex life, it may explain why he never had any children.

Rumors of Hitler’s intimate health issue have lingered since the second World War, but these were famously denied by Hitler’s childhood doctor, Dr. Eduard Bloch, who told American interrogators in 1943 that Hitler’s genitals were “completely normal,” The Telegraph reported. However, recently Professor Peter Fleischmann of Erlangen-Nuremberg University, a German historian, claims to have found indisputable proof that the rumors are true and the once leader of the Third Reich did indeed have only one functional testicle, The German newspaper Die Welt reported.

Before his rise to power in early 1933, Hitler took part in a failed military coup known as Munich Beer Hall Putsch. Here, Hitler and the Nazi party unsuccessfully attempted to gain control of the German government. Following the defeat, Hitler and other Nazi leaders were sent to Landsberg prison. Here, Hitler was sentenced to five years but served only eight months. During his incarnation, as was protocol, Hitler was given a full-body examination by a prison doctor. It was here, according to Fleischmann, that doctors discovered that Hitler’s right testicle still remained inside of his body.

“The testicle was probably stunted,” Fleischman said, as reported by The Telegraph.

What Is Cryptorchidism?

The condition is known as cryptorchidism and occurs in around 1 to 2 percent of male baby boys, The Boston Children’s Hospital reported. Normally, when a baby boy develops in his mother’s womb, the testicles form inside of the abdomen and drop into the scrotum right before birth. However, in boys with cryptorchidism either one or both testicles fail to drop following birth. Some undescended testicles will fall into the correct position within the first few months of a baby’s life, but those which do not may need a surgical intervention.

If the condition is not dealt with, the sperm inside the testicles may be impaired due to sperm’s need to be stored at a slightly cooler temperature. Although Hitler was known to have suffered from impotence in his life, the undescended testicle would not have been the cause of this. Other than decreased fertility, the condition is not known to be associated with any other serious health concerns, although a 2012 report did find that boys born with undescended testicles had a higher chance of developing testicular cancer.