The Original Universe’s Joe’s Dad was Joe with a beard. But Walkyverse Joe has a beard now, so I decided to grizzle up Dr. Richard Rosenthal’s beard a bit in the Dumbiverse. That’s right, he’s a doctor. A BONE doctor.
He is not above using wordplay to that effect to try to pick up chicks. It might be why he chose that specialty.
(Weirdly and completely coincidentally, today’s republished Roomies! strip is kind of pertinent, in a cross-universal sort of way.)