People were rather fond of infantile, cutesy names for their daughters back in the 50s. Gee, I wonder why? This name has only been used in America, as far as I know, and that would be my guess, and it sounds like ''duddy'' in American pronunciation.
i think it is cute, i heard it in pee wee's big adventure and i thought it is cute that his friends name was Dottie, i didn't even know it could be a real name,so i searched it.