Consider two-child families in which the parents have been identified as carriers of an autosomal recessive gene by virtue of having at least one child with the phenotype. When the children of many such two-child families are totaled, what proportion of children in these families will show the phenotype? (Hint: The answer is NOT twenty five percent!)
This problem is solved.
Parents must both be heterozygous. For two-child families, there are only four possibilities in regards to the trait.
1. First child has it and ...
Mendelian heredity is explained.