More than 200,000 American men are impotent as a result of falls onto the crossbars of bicycles, according to researchers from the Boston University School of Medicine. Such falls account for a full third of all cases of impotence resulting from injuries to the groin, the team reported in the Journal of Urology.

Other sports-related injuries that cause impotence include falls onto gymnastic parallel bars, trampoline springs and the backs of horses, and the impact of water during water ski and powered-ski accidents. The team called for the development of effective protective devices for use during sports and the redesign of bicycles and other hazardous sporting equipment.