Both members of a couple are carriers for a recessive disease allele. If the couple has four children, which of the following statements must be true?

Question

Quizplus · Accepted Answer

If both members of a couple are carriers for a recessive disease, then each child has a 25% chance of inheriting two copies of the disease allele and having the disease, a 50% chance of being a carrier like their parents, and a 25% chance of not inheriting the disease allele at all. Therefore, it is possible that none of the children have the disease, but all of them could be carriers. So option A and B are not always true. Additionally, the inheritance of the disease is not linked to the sex of the child, so option C is also not true. The only statement that must be true is that 50% of the children could be carriers of the disease, so option D is correct.

Both Members of a Couple Are Carriers for a Recessive