Question

Explain the concern over lethal genes and why the odds are usually in your favor in not having a child with an genetic affliction

Answer 1

Lethal genes are the ones that when expressed induce lethality in an individual. These are usually recessive and hence will be expressed only in the homozygous case.

Being lethal, they are present in the population only in the heterozygous state and become rare as the individuals mate to produce more and more homozygous dominant normal offsprings.

The odds of this happening are very low. This is because the lethal genes are very rarely present. Also, given that they express themselves only in the homzygous state further reduces their occurence.