"Herbert was not originally a pedophile; Henry pitched the idea to the writers of the show, leading to the decision to make him one. As with most of the other characters he created, Henry voices Herbert. Henry based Herbert's voice and appearance on an elderly man he met when he worked in a grocery store when he was in high school. In an interview Henry described that man as a sweet person."
http://en.wikipedia.org/wiki/Herbert_%28Family_Guy%29
