The son is George Walker Bush
He was KNOWN as Edgar Allen Poe.
Save the superciliousness for a more appropriate forum.
Marquez was his mother's maiden name (just as Fitzgerald was JKF's mother Rose's middle name.
Joyner was Joyner-Kersee's maiden name before she got married.
So, García's "everyday's" name is Gabriel García. But, since this is a rather common name-surname combo, the maternal surname is used to further identify him: Gabriel García Márquez.