**Core Concept:** Sickle cell anemia is an autosomal recessive genetic disorder caused by the inheritance of two mutated hemoglobin genes. Hemoglobin is the protein found in red blood cells that carries oxygen. In sickle cell anemia, the abnormal hemoglobin (HbS) causes red blood cells to become misshapen (sickle-shaped) and sticky, leading to reduced blood flow, organ damage, and an increased risk of infections.

**Why the Correct Answer is Right:** When both parents are sickle cell anemia patients, there is a 25% chance of their child inheriting the disease. This is because sickle cell anemia is an autosomal recessive disorder. In an autosomal recessive trait, an individual must inherit two mutated alleles (one from each parent) to have the disease. In this scenario, the parents are carriers of the disease, and each child has a 25% chance of inheriting the disease.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because only one mutated allele is needed for the child to be a carrier, not affected. In this case, both parents are sickle cell anemia patients.

B. This option is incorrect as it mentions that the child will be affected, but the explanation for this answer is incorrect because it only requires one mutated allele for the child to be a carrier, not affected.

C. This option is incorrect because it suggests that there is a 50% chance of the child being affected, but in reality, only one mutated allele is needed for the child to be a carrier.

D. This option is incorrect as it mentions that the child will be a carrier, but the explanation for this answer is incorrect because it only requires one mutated allele for the child to be a carrier, not affected.

**Clinical Pearl:** When both parents are sickle cell anemia carriers, there is a 25% chance of their child being affected, meaning the child has the disease. The remaining 75% of the children will be carriers, meaning they have two normal alleles for hemoglobin but are heterozygous for sickle cell trait. In summary, the correct answer is B: "There is a 75% chance that the child will be a carrier and a 25% chance that the child will have sickle cell disease."