A couple are both phenotypically normal, but their son suffers from hemophilia, a sex-linked recessive disorder. What fraction of their children are likely to suffer from hemophilia? What fraction are likely to be carriers?

Verified step by step guidance

1. Identify the mode of inheritance for hemophilia, which is a sex-linked recessive disorder. This means the gene causing hemophilia is located on the X chromosome.
2. Determine the genotypes of the parents. Since the son has hemophilia and it is a recessive disorder, he must have inherited the hemophilia allele from his mother, making her a carrier (XhX). The father must be normal (XY) as he does not show symptoms of hemophilia.
3. Set up a Punnett square using the mother's genotype (XhX) and the father's genotype (XY). This will help predict the possible genotypes of their offspring.
4. Analyze the Punnett square to determine the probability of each genotype among the offspring. The possible genotypes are: normal daughter (XX), carrier daughter (XhX), normal son (XY), and son with hemophilia (XhY).
5. Calculate the fraction of children likely to suffer from hemophilia (sons with XhY) and the fraction likely to be carriers (daughters with XhX).