The data in this study indicate that, on a gross society basis, male parts are more often injured by products than are female parts, and that sporting goods are often involved, though more often for younger males than older ones, and that, sporting good aside, zippers are often implicated.
“Product Related Adult Genitourinary Injuries Treated in United States Emergency Departments from 2002 – 2010,” Herman S. Bagga [pictured here, some years ago when he was still in medical school], Gregory E. Tasian, Patrick B. Fisher, Charles E. McCulloch, Jack W. McAninch, Benjamin N. Breyer, Journal of Urology, epub November 2, 2012.
The general picture is discernable when one combines the impact of Figure Two and Figure Three from the study, reproduced here On can also infer that, in general, as people gain decades of experience, they grow more skillful at shaving:
(Thanks to investigator James Harkin for bringing this to our attention.)