Kerry Washington is opening up about a startling revelation regarding her parents.   The Scandal actress opens up in her new memoir, “Thicker Than Water,” about her parents omitting the information in order to keep quiet about their fertility problems   The 46-year-old star shares that she recently learned that her father, Earl Washington, is not her biological father.    “It really turned my world upside down,” Washington tells PEOPLE in next week’s issue.   The actress explains that she …