When David and Patrick's mom first comes to visit she says David is her favorite because he just slipped out, but was in labor with Patrick for some time. Its a joke for several reasons. The first is because Shirley Jones and David Cassidy played mother and son on The Partridge Family and people still think she is his mother because she had been married to his dad. The second is that she is the real life mother of Patrick Cassidy who is the second of the three children she had with Jack Cassidy.