Suppose two individuals who are both heterozygous for brown

Suppose two individuals who are both heterozygous for brown eyes (brown is dominant over blue) and heterozygous for sickle-cell anemia. If they have 4 children, what are the odds that they will have 1 child with blue eyes and sickle-cell anemia?

Solution

Since both parents are heterozygous both brown eyes (Bb) and sickle cell anemia (Hb^SHb^s). sickle cell anemia is autosomal recessive disorder.
Probability of a child with blue eyes= Bb x Bb= 1/4 bb
Probability of a child with sickle cell anemia= Hb^SHb^s x Hb^SHb^s = 1/4Hb^sHb^s
SO the probability of a child with blue eyes and sickle cell anemia (bbHb^sHb^s)= 1/4bb x 1/4Hb^sHb^s= 1/16