What is recessive inheritance?
If two parents are both carriers of a genetic condition with a recessive inheritance pattern, there is a one-in-four chance that each child will be affected. So on average, one-quarter of their children will be affected. There is also a one-in-two chance that each child will be an unaffected carrier, like the parents. Examples of genetic conditions that show a recessive pattern of inheritance are cystic fibrosis, sickle-cell disease, Tay-Sachs disease and phenylketoneuria.