Given that the parents are not colorblind, but the son is, this means the mother must be a carrier because only females can be carriers for colorblindness.
This means that:
1. The genotype of the dad is XAY
2. The genotype of the mom is XAXa
Let's make a Punnett's square:
This means that the ratios would be as follows:
3. Genotype ratios:
25% XAXA
25% XAY
25% XAXa
25% XaY
4. Phenotype ratios:
25% Normal female
25% Normal male
25% Carrier female with normal vision
25% Colorblind male
