In 1983, the Journal of the American Medical Association called for a ban on boxing. The editor, George Lundberg, called boxing an “obscenity” that “should not be sanctioned by any civilized society.” Since then, the American Neurological Association, the American Academy of Neurology and the British, Canadian and Australian medical associations have also called for abolishing the sport.

Among boxers with 20 or more professional fights, the AMA says three out of four show brain deterioration.