Because he has no legal right to them. He isn't her husband, her legal guardian, or her doctor. Medical records are confidential, to protect the patient's privacy. (That means Mr. Rove's are confidential too-- a curious reporter concerned about Mr. Rove's sudden weight gain, for example, could not see the records of his physical exam without his permission.) There is no reason why Mr. Rove should have access to Hillary Clinton's confidential medical records, since he is not treating her for any illnesses.
It should also be noted that not releasing one's medical records does not mean a person has something to hide. Most presidential candidates do release the results of their physical exams, but candidates have every right to keep certain records confidential. Further, it should be noted that Karl Rove is a Republican political operative. His job is to create doubt about Democrats. There is no credible evidence that Hillary Clinton is seriously ill, but Rove's job is to make you think she is. It's sad, but that's politics.
Name at birth: Hillary Diane Rodham
Caucasian
Hillary Rodham Clinton's birth name is Rodham, Hillary Diane.
Hillary Rodaham
Hillary Rodham Clinton is commonly known as Hillary Clinton. She is also referred to by her supporters as "Hill" or "HRC."
Hillary Rodham Clinton was born on October 26, 1947.
Rodham - Hillary Diane Rodham
Hillary Rodham Clinton was born on October 26, 1947.
Hillary Clinton's father is Hugh Ellsworth Rodham.
Hillary Rodham Clinton.
Hillary Diane Rodham Clinton was born in Chicago, Illinois on October 26, 1947. When she was three, her family moved to Park Ridge, Illinois. Chappaqua, New York is her adopted hometown.
Hillary Rodham Clinton