a man who is affected with phenylketonuria marries a woman who is heterozygous at that locus. what is the probability that their first child will have phenylketonuria? a man who is affected with phenylketonuria marries a woman who is heterozygous at that locus. what is the probability that their first child will have phenylketonuria? 1/8 1/4 1/3 1/2 2/3
