The rarest hair color is red, with only 1-2% of the world's population having natural red hair. Red hair is caused by a mutation in the MC1R gene, which reduces the production of the pigment melanin. Melanin is responsible for giving hair its color, so a lack of melanin results in red hair. Red hair is most common in people of Celtic descent, but it can also be found in people of other ethnicities.
Red hair has been associated with a number of positive and negative traits throughout history. In some cultures, red hair was seen as a sign of beauty and good luck, while in other cultures it was seen as a sign of witchcraft or evil. Today, red hair is generally seen as a unique and attractive trait.
