गूफ़

In the final season, there is a story line about Sarah's biological father and blood types. Both William Walker and Nick Brody have type B blood, and it was revealed in a previous season that Nora has type O blood. Sarah's blood type is said to be AB, but this is impossible. For a child to have type AB blood, there must be some combination of A and B. Either one parent is A and the other is B, or one parent is AB and the other has any other type. If Nora has O and both fathers have B, Sarah must have either type O or B blood.