Conversation so far:
Where was Mantle born?
Mantle was born on October 20, 1931 in Spavinaw, Oklahoma.
What did his parents do?
the son of Lovell (nee Richardson) Mantle (1904-1995) and lead miner Elvin Charles "Mutt" Mantle (1912-1952).
Where did he go to school?
Mantle was an all-around athlete at Commerce High School, playing basketball as well as football.
Did he go to college?
(a halfback, he was offered a football scholarship by the University of Oklahoma) in addition to his first love, baseball.
What was his major in college?
CANNOTANSWER.
Are there any other interesting aspects about this article?
Kicked in the left shin during a practice game during his sophomore year, Mantle developed osteomyelitis in his left ankle, a crippling disease.
Did the disease stop him from playing ever?
Mantle's parents drove him at midnight to Oklahoma City, Oklahoma, where he was treated at the Children's Hospital with the newly available penicillin.

Question: When did he decide to stop playing football?
Self-contained rewrite: When did Mickey Mantle decide to stop playing football?