Dickie Duck's grandfather might be (or possibly was) an anthropomorphic duck.
Goldie O'Gilt is known to have had an anonymous daughter. However, with whom is unknown. Some people theorize that said daughter was in fact the illegitimate daughter of Goldie and Scrooge McDuck. However, others argue that Goldie was probably married with an unknown man at some point between Scrooge's departure from the Klondike (in 1899) and the two's reunion in 1953.