A carrier mother (X^H X^h) and an unaffected father (X^H Y) have a son. What is the chance he has an X-linked recessive disorder?
Answer and explanation
Correct answer: C. 50%
- Step 1: The son gets Y from the father and one X from the mother. Step 2. He inherits the X^h with probability 1/2. Answer: 50%. Why not the others: 25% is the chance for any child, 100% and 0% ignore the carrier.
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