Medical research has conclusively proven something that has been intuitively understood for decades: professional wrestlers lack the ability to grow underarm hair.

A new report published this week by scientists at the Harvard Center for Follicular Research concluded that “men and women who engage in long-term sports-entertaining almost universally develop underarmular alopecia.”

The reasons behind underarmular alopecia — or “wrestler pattern baldness,” in lay terms — are unclear, but the condition is believed to be linked to other wrestling-related ailments including orange skin, raspy voice, short temper, and chronic spandex rash.

In very rare cases, such as George Steele and Kevin Owens, a moderate amount of armpit hair is present, which has led researchers to believe the condition may be related to body fat percentage.

A minority of skeptics suggest that wrestler pattern baldness is not a medical condition at all, but rather the result of wrestlers shaving their underarms. But that is clearly not true, because the burly brawlers of WWE surely wouldn’t be so vain and body-conscious.