Multiple choice

When a man with hypertrichosis marries a normal woman, what percentage of their sons would be expected to have hairy ears?

  1. 50%

  2. 100%

  3. 0%

  4. 25%

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hypertrichosis (hairy ears) is a Y-linked trait, meaning the gene is located on the Y chromosome. A male with this trait passes his Y chromosome to all his sons. Since the mother is normal (no Y chromosome), 100% of sons will inherit the father's Y chromosome and thus express the trait.