14. Optional Challenge Question: In humans, there is a dominant allele that causes vitiligo, where small-unpigmented spots appear on the body. Also, there is a recessive allele for another gene that causes albinism, which causes the entire body to be unpigmented. Vitiligo cannot be seen in albinos. A man (Paul) with vitiligo had an albino mother and father with normal skin pigmentation. Paul has a child with a woman (Sandra) with normal skin pigmentation. However, Sandra has an albino father. What is the probability of having Paul and Sandra having a phenotypically normal child?