Craig Benzine aka Wheezy Waiter of the Mental Floss series “Big Questions“ very quickly and concisely explained the genetic and biological reasons explaining why some people have curly hair and while others have straight hair in answer to a viewer’s question.
What makes hair appear a certain way? When they’re actually affected at the follicle level. A hair follicle is a tiny organ beneath the skin that produces hair. For hair to grow, it has to be forced through a tube whose shape affects the hair. People with curly hair have asymmetrical follicles…which grow oval hair that curls.