If a child has blond hair and both of her parents have brown hair what does that tell you about the allele for blond hair?

Both of the parents were heterozygous with the blonde hair allele, which is recessive. When there are two parents that are heterozygous, there is a 25% chance their offspring will get two of the recessive alleles. A punnett square can be useful when determining the different phenotypes and genotypes possible in offspring