Why is it not possible to get a colorblind female from a normal male and a heterozygous female?

Color blindness is typically inherited as an X-linked recessive trait. A colorblind female must have two copies of the colorblind allele (one from each parent), meaning she must inherit the allele from both her mother and father. In this scenario, the normal male (with a normal X chromosome) can only pass on a normal X chromosome to his daughters, while the heterozygous female has one normal X and one colorblind X, meaning she can pass on either allele. Therefore, the combination of a normal male and a heterozygous female cannot produce a colorblind daughter.