Why do some women never grow hair on their legs or armpits?

One of my acquaintances has absolutely no hair on her armpits or her legs. She claims this is because her mother told her never to shave, so she didn't; therefore, no hair grew. She is a brunette, so I find it strange that she has no hair, even in her armpits. I suspect it is because she is deficient in some hormone (but which one?)Why do some women never grow hair on their legs or armpits?
could be testosterone. i think that's the hormone that causes hair? she must have really low levels. lucky!Why do some women never grow hair on their legs or armpits?
Every girl is different. You can't expect the same thing in every girl.