Question

A woman is deaf because of being homozygous recessive at an autosomal locus. She marries a deaf man who is also homozygous recessive at an autosomal locus. They have two children who have normal hearing. Assuming that this couple is the biological parents of these children, how is this situation most reasonably explained?

Answer 1

The correct answer is because of the mutant allele shows reduced penetrance and the normal son carries the mutant allele.