From the article:
A Mason City man is being treated for a gunshot wound to the knee after his 4-year-old son picked up a handgun and it fired.
Police say 29-year-old Christopher Upenieks (OOP-in-icks) was accidentally shot Monday afternoon when the boy found the unsecured weapon in his dad's truck, picked it up and it fired.
Upenieks was in his truck when police arrived. He was taken to a hospital with non-life threatening injuries. Police say he had a valid permit to carry a gun.
Every gun in the hands of a child must first pass through the hands of an adult.
UPDATE (5/28/12): The man got off with just a fine. From a follow-up article:
The Mason City Globe Gazette reports that 29-year-old Christopher Upenieks had pleaded guilty to misdemeanor child endangerment after prosecutors agreed to drop a charge of allowing a minor access to a loaded firearm..