When the person who was eventually given the stage name John Wayne was born in Winterset (NOT Waterloo), "Marion Robert Morrson" was written on his birth certificate.
Most sources have his birth name as Marion Michael Morrison. Robert was his younger brother's name. I doubt that his parents would give both boys the same name. The parents changed Marion's middle name to Michael upon the birth of the boy they named "Robert."
Wayne's oldest son was named Michael, using what was his father's middle name at the time.
John Wayne Gacy's birth name is John Wayne Gacy Jr..
Brendan Wayne is John Wayne's grand-son, and appears in that film.
Hatari!
Nate Wayne's birth name is Nathaniel Wayne.
Wayne Newton's birth name is Newton, Carson Wayne.
Ethan Wayne's birth name is Wayne, John Ethan.
Wayne Chrebet's birth name is Wayne John Chrebet Jr..
John Caler's birth name is John Wayne Caler.
John Wayne Gacy's birth name is John Wayne Gacy Jr..
John Wayne name was Marion Morrison
Brendan Wayne is John Wayne's grand-son, and appears in that film.
Marion Morrison.
Hatari!
Marion Robert Morrison.
Wayne Coy's birth name is A. Wayne Coy.
Nate Wayne's birth name is Nathaniel Wayne.
Wayne Swan's birth name is Wayne Maxwell Swan.