What is the probability that a sixth child, of carriers of sickle cell anemia, will have the condition if previous children have mixed results?

To determine the probability that a sixth child of two carriers of sickle cell anemia will have the condition, it's essential to understand the genetic principles involved. Sickle cell anemia is an autosomal recessive disorder, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to express the condition.

When both parents are carriers (each having one normal allele and one mutated allele, represented as Aa), the possible genetic combinations for their children can be derived from a Punnett square. The combinations are:

1. AA (homozygous dominant, normal)

2. Aa (heterozygous, carrier, normal)

3. Aa (heterozygous, carrier, normal)

4. aa (homozygous recessive, affected)

From this, we can see that:

• There is a 1 in 4 chance (or 25% probability) that a child will inherit the homozygous recessive condition (aa) and therefore have sickle cell anemia.

• There is a 3 in 4 chance (or 75% probability) that the child will not have the disease (either AA or Aa).

The probability doesn't change with each successive child if both parents maintain the carrier status