Why Do Some People Have Curly Hair and Others Have Straight Hair?

Hair is like a rope made of tiny strings. Some people have more strings that twist together, making their hair curly. Others have fewer strings or ones that don’t twist as much, so their hair is straight.

A special protein called keratin helps build your hair. When you have a certain type of protein shape, it creates curls. If your hair has a different kind of shape, it stays straight. That’s why siblings can look different even though they come from the same family.