It has long been suspected that Hitler's conquest of Europe was an attempt to compensate for a lack of potency elsewhere.
But the notorious playground rhyme about his testicles appears to have only told half the story, as a book claims the leader of the Third Reich had a micropenis.
Hitler suffered from a condition called hypospadias which left him with an abnormally small manhood, according to historians Jonathan Mayo and Emma Craigie.
In their book Hitler's Last Day: Minute by Minute, they say they have uncovered medical records which confirm the Fuhrer's embarrassing deformity.
The condition is so severe that sufferers have to urinate from a hole at the base of the shaft, instead of the tip.