Heredity Word Problem

Red hair is recessive (r), while blond hair is dominant (R). If a red-haired woman marries a blond-haired man, what are the possible genotypes of the parents if 100% of their children will be blonde? Please show your work through a Punnett Square.

Known information:

Blond hair = dominant
Red hair = recessive

The red-haired woman's genotype has to be rr, since blond hair is dominant (recessive alleles require 2 copies of it to show in the phenotype).

The blond-haired man's genotype can either be Rr, or RR.

Rr:     ___r_______r___

     R |__Rr___|__Rr___|            With Rr, 50% will have blond hair, while 50% will have red hair.

     r  |__rr____|___rr___|  

RR:   ___r_______r___

     R |__Rr___|__Rr___|            With RR, 100% will have blond hair.

     R |__Rr___|__Rr___|  

Therefore, the genotypes of the parents are rr (red-haired woman) and RR (blond-haired man). RR x rr

His genotype is Rr, and the dominant allele is expressed in his phenotype, which is having blond hair.

*I made up the genotype of the blond-haired boy in the picture so it would fit in with the problem.