If both parents are carriers for Thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

Shutterstock Explore Since both parents are carriers (heterozygous, $Aa$), the cross is $Aa\times Aa$.The possible genotypes of the offspring are $AA$ (Normal), $Aa$ (Carrier), $Aa$ (Carrier), and $aa$ (Affected).The probability of an affected child ($aa$) is $1$ out of $4$, which is $25\%$.