Former US President George H.W. Bush (R) watches as his son, former US President George W. Bush, throws a ceremonial first pitch prior to the start of Game 4 of Major League Baseball's World Series between the San Francisco Giants and the Texas Rangers, in Arlington, Texas, Oct 31, 2010. [Photo/Agencies]

Former President George H.W. Bush (C) reaches to shake hands with San Francisco Giants' Cody Ross (13), as Bush's son, former President George W. Bush (R), drives to the mound to throw the ceremonial first pitch before Game 4 of Major League Baseball's World Series between the Giants and the Texas Rangers in Arlington, Texas, Oct 31, 2010. [Photo/Agencies]