Source: Per news clipping post by David Archer at 18th Battalion Facebook Page (not group).
Family Search: When Private Peter J. McGinn was born on 20 March 1899, in Toronto, Ontario, Canada, his father, Patrick McGinn, was 44 and his mother, Essie O’Connor, was 41. He lived in Toronto, York, Ontario, Canada for about 6 years. He registered for military service in 1915. In 1915, at the age of 16, his occupation is listed as labourer.
This man enlisted using his year of birth as 1897 when he was actually born in 1899. Wounded at the Battle of Flers-Courcelette, September 15, 1916. Enlisted under age.
History of the 18th Battalion CEF, "The Fighting Eighteenth" 