Head hair comes in many colours, shapes and sizes, and hairstyles are often an expression of personal style or cultural identity. Many different genes determine our hair texture, thickness and colour.

Wavy hairstyles are all the rage, even among people with straight hair. But using a curling iron is fiddly and time-consuming and you also risk singeing your hair. So if you want to keep your curls ...

This podcast was produced for L’Oréal Groupe by Scientific American Custom Media, a division separate from the magazine’s board of editors. Whether your hair is curly, straight or something in between ...