Originally Posted by
Capnplank
I don't know if or where he's talked about it, but here's one clue I've found:
In Vienna John Irving studied under Gunter Grass. This time and the influence of the acclaimed writer appears to have had a profound effect on Irving. Owen, the main character in Irving’s seventh novel, A Prayer for Owen Meany, seems to have been loosely based on Grass’s character Oskar Matzerath. As a hint, Irving has given his character initials identical to those of the protagonist in Grass’s The Tin Drum. Beyond that, the stories are often antithetical. Whereas Owen cannot help his prepubescent stature and characteristics, Oskar seems to have chosen his. Owen predicts a future that he cannot control; Oskar is in control of his own destiny. However, both characters are old beyond their years, despite their childish physical characteristics.