Why is some hair curly and others not?

[PLAOH]

What is the reason why some hair has a natural curl and others are dead straight. I'm sure I've heard somewhere that curly hair lacks moisture, hence it curls!! Can anyone confirm if this is true, or have I just imagined it:lol:

My hair has a natural curl and is a pain whilst I try and grow it (again). Would using a shampoo with moisture help keep it straighter??

 

[Katelisa]

Its due to the shape of the hair shaft i think. straight ones grow straight hairs, curved ones grow curly hair...

 

[BABSann]

Variations in Hair Structure - straight, curly, wavy hair
Have a look at this.HTH

 

[Amanda2114]

Whether your hair is curly or straight is down to your genes. However, the way in which genes control the shape of your hair is widely debated. Once upon a time scientists believed that how curly hair was depended on the individual hair shafts, they have since found out that the shape of the folliclue determines the shape and angle that hair grows.