Joel Kaplan was the father of Olive Kaplan, an infant clinic patient in the Season 1 episode Babies & Bathwater. Joel is married to Rachel Kaplan, Olive's mother. Joel was portrayed by actor Michael Simpson. Joel and Rachel came back to Dr. House. He tried to avoid them, but they swore to him that Olive's diet had been recommended by a university educated nutritionist, Rachel's uncle. They also informed him they fed her whenever she was hungry. Dr. House was intrigued and agreed to run more tests.