Why Red Hair Remains Rare: Evolutionary Biology Explains the 2% Phenomenon

Among the visible signatures of human genetic history, red hair stands as one of the rarest — carried by only two in every hundred people on Earth. Its scarcity is not accidental but mathematical, the product of a recessive gene that demands two copies to speak aloud, and a geographic story of ancient migrations and isolated populations where chance, not design, concentrated a particular variant in the Celtic north. To ask why red hair is rare is to ask how evolution writes itself quietly into the body, leaving traces that outlast the civilizations that once marveled at them.