The first jockstrap was introduced in the United States in 1874. It was quickly adopted as a standard testicular guard by hockey players.
But it wasn't until 1979 that the National Hockey League made helmets mandatory -- which produced much grumbling by the players.
In other words, it took over 100 years for hockey players to decide that their brains are as important as their balls.
When I told this little factoid to my girlfriend, she rolled her eyes and said "Men! You have your brains between your legs!"
"Yeah," I admitted. "But you know, that gives me a mind-blowing idea...."
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(True story: The word "jockstrap", by the way, came from "jockey strap" -- jockey meaning "rider", as it does today. They were used by both horsemen and early bicycle riders to protect the genitals; "jock" was used as slang for penis from about 1650 to 1850. The word "jock" meaning "athlete" came from "jockstrap". So, in a very real sense, the full-of-themselves guys who called themselves "jocks" in high school were actually calling themselves dicks.)