Concept:The sex of an offspring is determined by the father (Y = son, X = daughter), but a son's X-linked traits are inherited exclusively from the mother.
Solution:- Mother's genotype: Carrier (\(X^H X^h\)).
- Father's genotype: Affected (\(X^h Y\)).
- When determining the probability of traits in sons, we only look at the X chromosome provided by the mother (since the father must provide the Y).
- The mother has a 50% chance of passing the healthy \(X^H\) allele and a 50% chance of passing the mutant \(X^h\) allele.
- Therefore, exactly 50% of their sons will be affected by hemophilia.
Why other options are incorrect:- The father's affected status is irrelevant to the sons, as he only passes them a healthy Y chromosome. The probability is entirely dictated by the mother's heterozygosity.
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