She didn't know her dad and all she had was a name that was hand-written on her birth certificate. Once contacted, the brother agreed to do the Ancestry test. It confirmed that they are siblings. She is 4 months older that her sister. The brother & sister never knew that they had a sibling out there. Their father went to the grave with that secret. MIL's mom did say that he knew about my MIL, but went back to his family. Not sure if his wife ever knew.