Members of an elite German military unit are experiencing a bizarre physical phenomenon as a result of their drill training techniques.
The condition, called one-sided gynecomastia, is a result of the way the soldiers perform their drills, with the repeated slapping of a rifle against the left side of the chest stimulating hormones on that side of the body.
Seventy-four percent of the soldiers have been diagnosed with gynecomastia, after complaining of growths on the left side of their chests.
Professor Bjorn Krapohl, director of plastic surgery at the military hospital in 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 Wachbataillon is known for performing drill demonstrations at major events, such as the ceremonial oath of the Bundeswehr ceremony.
It is the largest battalion of German forces, consisting of about 1,800 soldiers.
An army spokesman said: "The affected soldiers are being medically supervised and treated individually."
No mention was made of any amendments to the battalion's undergarment policy.