زوجان كلاهما حامل لصفة الأنيميا المنجلية. ما احتمال أن يكون طفلهما مصاباً بالمرض في كل حمل؟

Both partners carry the sickle cell trait. What is the chance their child has the disease in each pregnancy?

1. 100%
2. 25%
3. 75%
4. 50%

Answer: B) 25%. Inheritance is recessive: each pregnancy has a 25% chance of disease, 50% carrier and 25% unaffected, hence premarital screening.