Redhead is a person with red or reddish-tinted hair. Approximately 1 to 2% of the world's population has red hair.
Red hair is made by genes. The gene for red hair is recessive, meaning to be weaker than other genes, like the brown hair gene, for example. Because of this, in order to have natural red hair a person needs to have red-haired ancestors present on both the maternal (mother's) and paternal (father's) side of the family.
Scotland has the most red-headed people in Europe, with 13% of Europe's redheads living there. Ireland has the second highest amount of redheads in Europe, with 10% of Europe's redheads living there, despite Ireland being the country most associated with red hair.
Depite all this, the US has the largest number of redheads living there in the world (up to 18 million compared to 650,000 redheads living in Scotland).
In some countries, particularly the British Isles, despite the high proportion of redheads there, redheads are sometimes given rude names such as "carrot-top" and "ginga", and are in some cases heavily ridiculed (made fun of) by their peers. In some extreme cases, people have been harassed (others have behaved threateningly towards them) for having red hair.