19th Century Gentlemanscaping
Way back in the entirety of the 19th Century, men's vital arteries were located entirely in their balls (then referred to as "The Danger Zone"). Sure, it made the rest of their bodies tough enough to handle the depression, but it made pubestripping a real danger. So using the power of concentration, they willed all their vitals to different parts of their bodies, and by 1986 the evolution was complete. Kenny Loggins even commemorated the death of the Danger Zone with a song, and all was right with the world.