In this connection it is said that only the three patriarchs Abraham, Isaac, and Jacob may correctly be called the fathers of the Hebrew race, and only the four women Sarah, Rebekah, Rachel, and Leah, the matriarchs.
One primary source of lenient application focuses on the beraita of Evel Rabbati (Semachot);
Evel Knievel | The 'No Motor Vehicles' sign, sometimes colloquially called the Evel Knievel | Evel Rabbati |