* Genetics

* Red hair comes about due to a pigment called pheomelanin

* Red hair is generally thought of as a recessive gene. It may skip generations.· However, as with other pigments that determine eye and skin colour, the red hair gene can often be seen in varying shades, such as strawberry blonde or dark auburn hair - depending upon how much pheomelanin is present.

* Both parents must have the red hair gene (not necessarily red hair) for their child to have red hair.· Professor Jonathan Rees conducted a study of redheads at Edinburgh University. He identified the "gene for red hair" the melanocortin 1 receptor.

* Professor Rees found that this single gene, carried by up to 40% of Scots, was responsible for red hair. He estimated that the first human redheads walked this earth 50,000 years ago and then spread throughout northern Europe.

* People with dangerous variants of a gene called the melanocortin-1 receptor (MC1R) have at least double the risk of contracting skin cancer, even if they have medium or olive skin.