Mendelian inheritance · USMLE Step 1

If a father has an X-linked recessive disorder, which of his children are guaranteed to inherit the mutant allele?

  1. All sons
  2. All daughters
  3. Half of sons
  4. Half of daughters
Show answer and explanation

Correct answer: All daughters

Fathers pass their X chromosome exclusively to all daughters. Sons inherit the Y chromosome instead. Thus, all daughters are obligate carriers unless the disorder is dominant.

Difficulty: Medium Question 2 of 20

Practice all 20 Mendelian inheritance questions

Keep practicing

More Mendelian inheritance questions