If a man and woman have five children, four are phenotypically normal and one has sickle cell anemia, what are the most likely genotypes of the parents?

The parents' most likely genotypes can be understood through the inheritance pattern of sickle cell anemia, which follows an autosomal recessive inheritance. To manifest the disease, an individual must inherit two copies of the sickle cell allele (HbS), which means they must have the genotype HbSHbS. Individuals who are carriers of the sickle cell trait (HbAHbS) have one normal allele (HbA) and one sickle cell allele (HbS) and typically exhibit normal phenotypes.

In this scenario, they have five children, four of whom show normal phenotypes and one who has sickle cell anemia. For a couple to have one child with sickle cell anemia and several normal children, it is necessary that both parents carry at least one copy of the sickle cell allele. If both parents had the genotype HbAHbA (homozygous normal), they would not be able to have a child with sickle cell anemia.

When both parents are heterozygous (HbAHbS), the potential offspring can be as follows:

• 25% (HbAHbA) – Normal

• 50% (HbAHbS) – Carrier, normal phenotype