In which situation can a child born with a genetic disease have two normal parents?

Question

Quizplus · Accepted Answer

If the genetic disease is recessive, then both parents can be carriers of the gene without showing symptoms. When both parents are carriers, there is a 25% chance for each child to inherit two copies of the defective gene and therefore have the disease. This can happen regardless of whether the gene is dominant or recessive, but if the gene is dominant, at least one parent would show symptoms, making it less likely for two normal parents to have a child with the disease.

In Which Situation Can a Child Born with a Genetic