STRAIGHT, WAVY OR CURLY HAIR

There is no perfect answer by now as to why some textures of hair are straight, wavy or curly. The debate within the scientific community attributes it to this:

Distribution of ortho- and para-cortex

Shape of hair bulb

Influence of Inner Root Sheet

Diameter of hair with one side of the hair bulb having a quicker cell division than the other

The facts:

Asian hair is rounded and straight

Caucasian hair shows a round to oval diameter and is straight but also tends to be wavy and curly

African hair has a very elliptic diameter and creates very tight curls