Why do so many men, despite hair colour, have ginger beards?

Ricky Gellatly, Oxford

Beard hair is quite different to head hair; it is coarser, curlier and doesn't fall out as we get older. Comparatively little work has been done on the genetics of human hair colour, but it is believed that in order to have a ginger beard you must be a carrier for the recessive gene on chromosome 4. With two copies of this gene you will have ginger hair all over, but with just one, the hair on your head will be brown or auburn and your beard will be ginger.

Submitted by Luis Villazon