It sounds like a joke from 'Allo, 'Allo: soldiers from a German elite fighting force are growing breasts.
According to a medical report, soldiers in the Wachbataillon unit have been slapping their rifles a bit too hard on the left side of their chests during drills.
The repeated slapping has stimulated the soldiers' glands, giving them breasts.
The condition is called one-sided gynecomastia and has affected three quarters of the battalion.
Professor Bjorn Krapohl, director of plastic surgery at the German Armed Forces Hospital of Berlin, told the German Herald: "There is a very significant link between the activity in the Guard Battalion and the development of the breast on the left side.
"They need to change the way they drill. The constant slamming of the rifles against the left hand side of the chest is clearly a significant factor."