A geneticist is studying the inheritance of a trait in humans. She observes that two siblings who are both carriers of a specific disease have offspring with a 50% chance of developing the disease. Which of the following is the most likely genotype of the affected offspring?

Core Concept

In a scenario where two siblings who are both carriers of a specific disease have offspring with a 50% chance of developing the disease, the most likely genotype of the affected offspring is Aa. This is because the offspring are likely to inherit one copy of the recessive allele from each parent, resulting in the expression of the disease.