Question

If both parents are carriers of sickle cell anemia then what is the ratio of progeny?
A. $1$ normal: $2$ sufferers: $1$ carrier
B. $1$ normal: $2$ carriers: $1$ sufferer
C. $1$ normal: $3$ carriers: $0$ sufferer
D. $2$ normal: $0$ carrier: $2$ sufferer

Answer 1

If the sickle cell anemia has two copies of sickle hemoglobin gene then they are affected by the sickle cell anemia. It is the recessive condition. Sickle cell trait occurs at the condition there is only one copy of sickle hemoglobin with one copy of usual hemoglobin. This is not a disease or illness but it is passed to the children.

Complete answer:
Option B: If both the parents are affected by the sickle cell anemia or trait then either half of the chance for getting sickle cell anemia for their children or completely unaffected. So the possibility is only one sufferer and one normal in the children's generation.
So option A is the correct answer.
Option A: If any one of the parents gets this anemia then anyone of the children is affected or both of them affected by the sickle cell anemia or trait.
So option A is not the correct answer.
Option C: Both the parents are affected by sickle cell anemia then there is any one of them is affected by anemia or no one is affected.
So option C is not the correct answer.
Option D: If both of the parents are not affected then both of the children are completely affected or completely unaffected. So it is possible if the previous generation is affected.
So option D is not the correct answer.

Note:
Sickle cell disease is the group of blood disorders caused by the mutation in the hemoglobin gene. The disease like hemoglobin SC and sickle beta thalassemia is caused by the mutated hemoglobin. Sickle cell or sickling also acts as the resistance to diseases like malaria. The United States people are largely suffering from this sickle cell anemia.