When a show has been on the air for nearly two decades, it’s understandable that a few plot lines may get recycled. After all, who’s really going to notice if four of the show’s leads are revealed to have massive tumors in a principal cast of over twenty-five characters? However, it's hard to believe that Meredith Grey would have two half-sisters who she knew nothing about and that both of those women would come work as surgeons at her specific hospital in Seattle.
This is not even mentioning Lexie Grey’s questionable medical timeline – she started her medical internship program when most students are finishing their undergraduate studies – or Meredith conveniently forgetting her mother’s pregnancy before Maggie Pierce was born in the '80s.