On September 10, 1963, Stan Musial became the first Grandfather in the history of Major League Baseball to hit a home run. Early that morning, around 4:40 a.m., Musial's son Dick and his wife Sharon welcomed Jeffery Stanton Musial into the world. With the classic smile on his face Musial came to the ballpark, was congratulated by teammates, then got ready to face the visiting Chicago Cubs. It did not take Stan long to become the first Grandpa to go deep in a ballgame. In fact he did it in his first at bat, in the first inning, and on the first pitch he saw, which was delivered by Glenn Hobbie. The two-run blast set the tone for the day, as the Cardinals rode the wave to an 8-0 victory. Bob Gibson also got in on the home run action, hitting a three-run shot in the second. Musial followed Gibby's shot with a single and a ribbie in the same inning. The home run that Musial hit that night in September was the 474th of his career. He hit one more before he hung up the cleats. Number 474 was quite special, as The Man welcomed a Little Man into the world in a very unique way.
Check out the box score here: http://www.baseball-reference.com/boxes/SLN/SLN196309100.shtml