Question

in which situation can a child born with a genetic disease have two normal parents?
a when the disease gene is dominant and the parents are heterozygous
b when the disease gene is recessive and the parents are heterozygous
c when the disease gene is either dominant or recessive
d it is not possible

Explanation:

When the disease gene is recessive, parents who are heterozygous (carriers) can pass on the recessive allele. In a recessive disorder, an individual needs two copies of the recessive allele (one from each parent) to express the disease. If the gene were dominant, a parent with the dominant allele (even as a heterozygote) would show the disease trait.

Answer:

B. When the disease gene is recessive and the parents are heterozygous