**Core Concept**
Sickle cell anemia is a genetic disorder caused by a mutation in the HBB gene that codes for the beta-globin subunit of hemoglobin. This mutation leads to the production of abnormal hemoglobin, known as hemoglobin S, which causes red blood cells to assume a sickle shape under low oxygen conditions. The inheritance pattern of sickle cell anemia is crucial for understanding its prevalence and management.

**Why the Correct Answer is Right**
Sickle cell anemia is inherited in an autosomal recessive manner, meaning that an individual must inherit two defective copies of the HBB gene (one from each parent) to express the disease. This is because the mutated gene is recessive, and individuals with one normal and one mutated gene (carriers) typically do not display symptoms but can pass the mutated gene to their offspring. The autosomal recessive inheritance pattern is a result of the dominant nature of the normal HBB gene and the recessive nature of the mutated HBB gene.

**Why Each Wrong Option is Incorrect**
**Option B:** Hemophilia is inherited in an X-linked recessive manner, not autosomal recessive. It is caused by mutations in genes that code for clotting factors, which are located on the X chromosome.

**Option C:** Hereditary spherocytosis is an autosomal dominant disorder, not autosomal recessive. It is caused by mutations in genes that code for proteins involved in the production of red blood cell membranes.

**Option D:** Glucose-6-phosphate dehydrogenase (G6PD) deficiency is inherited in an X-linked recessive manner, not autosomal recessive. It is caused by mutations in the G6PD gene, which codes for an enzyme involved in protecting red blood cells from oxidative damage.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the inheritance pattern of a genetic disorder can significantly impact its management and prevention strategies. For example, individuals with sickle cell anemia who are aware of their carrier status can make informed decisions about their reproductive choices to avoid passing the mutated gene to their offspring.

**✓ Correct Answer: A. Sickle cell anemia**