Genetic screening: For better or for worse?

Cystic fibrosis, sickle cell anemia, Tay-Sachs disease, and thalassemia are autosomal-recessive diseases that occur more frequently than once in 4,000 live births in subgroups of the American population. Tay-Sachs disease can be diagnosed by mid-trimester amniocentesis, a safe procedure.1 Early intrauterine detection of sickle cell anemia and thalassemia by placental aspiration has been reported2,3; the safety and accuracy of the techniques require confirmation. In the future, diagnosis of the 16-week fetus with cystic fibrosis will also be possible. Prenatal diagnosis could drastically reduce the incidence of these disorders, but there are two prerequisites. First, couples in whom both mates are carriers must be identified before they have any children.