This includes genetic tests used by couples whose families have a history of recessive genetic disorders and who are considering having children. Three common tests include those for cystic fibrosis, Tay-Sachs disease, and sickle cell. This is testing of a fetus. This may occur when there is a risk of bearing a child with genes associated with mental retardation or physical deterioration. One of the most common diseases screened by this method is Down syndrome.
Tests usually have clear benefit to the newborn because treatment is available.
Phenylketonuria and congenital hypothyroidism are conditions for which testing is conducted. These diseases are complex and have both genetic and environmental causes. Genetic tests may indicate a susceptibility or predisposition for these diseases. Huntington's Disease can also be tested by using this method. This is when you use genetic markers to identify unique characteristics of an individual.