I'm a 6'1" man with size 3 feet due to a mild deformity. I've never met another adult with smaller feet.
(lemmings.world)
Was born with super small feet in the 1st percentile as well as hands due to a benign genetic issue. Totally healthy but shoe shopping is always awkward. Have decent balance and can walk and run fine as my calf muscles are quite developed to compensate. No, the myth isn't true.
