"A report published in the German Medical Science journal revealed that dozens of soldiers in the Wachbataillon unit have developed one-sided gynecomastia, a condition that results in mammary growth due to over-stimulation to the area. As a part of the soldiers' trademark drill, the men violently slam their guns into the left side of their chest, causing the growth of a left boob."

from

http://www.heavy.com/regions/2013/01/german-soldiers-develope-breasts/