Students may wonder why they look the way they do. The answer lies in genetics, the branch of biology that deals with heredity and the variation of inherited traits. However, understanding how an organism's genetic code (i.e., genotype) affects its characteristics (i.e., phenotype) is more than a matter of idle curiosity: It's essential for understanding heredity and the processes of mutation and evolution. Yet, students often have trouble making the connection between genotype and phenotype. This article offers a simple way to illustrate that connection--through a discussion of human hair color. Students use hair color to make a clear connection between genotype and phenotype. (Contains 3 figures.)