Was Sally Ride really Jimmy Sizemore's sister?

A friend of mine emailed me this morning about Sally Ride, the USA's first female in space. He said:

It turns out that Jimmy Sizemore is really Sally Ride. At Swarthmore College she played golf, field hockey, and was the Eastern Intercollegiate Women's Tennis Singles champion. She transferred to Stanford and was #1 on Stanford's tennis team and later dabbled in professional tennis. She was a PhD in physics and was an astrophysicist, and of course an astronaut.
 
If you wonder what that is about you can read my first book: Be Sincere Even When You Don't Mean It, featuring Jimmy Sizemore. I'm thinking of writing a sequel: Jimmy Sizemore Goes to Mars.