Samuel Goldwyn was initially reluctant about making the film as he believed that baseball movies were box office poison. He was persuaded to do it when he viewed footage of Gehrig's famous farewell speech.
People have to live their own lives. Nobody can live it for you. Nobody could have made a baseball player out of Uncle Otto, and nobody can make anything but a baseball player out of me.
As Gehrig (Cooper) is doing his homework at Columbia, he writes with his right hand. Whilst Gehrig batted and threw left-handed, like many lefties of the era (perhaps because of "correction" in school), he wrote with his right hand.
Opening credits acknowledgment: Appreciation is expressed for the gracious assistance of Eleanor Gehrig (as Mrs. Lou Gehrig) and for the cooperation of link=nm1561994] (as Mr. Ed Barrow) and the New York Yankees arranged by Christy Walsh.
A colorized version is available.