A group of Orthodox Jews in New York and Israel are using genetic screening for young people. Schoolchildren have a blood test to see if they carry genes for any of three recessive diseases, Tay-Sachs, cystic fibrosis and Gaucher's disease. The results are stored as codes and if a boy and girl want to date they are encouraged to call the central office with their identification numbers. The goal is to discourage people from dating or marrying who are at risk of passing on inherited disorders. They are then told if their is a risk of having children with the diseases and may be offered genetic counselling. Prenatal testing is not generally unacceptable to Jews.
Genetic testing is full of complexities and pitfalls. Not only are there laboratory and human errors, but there are often enormous uncertainties about when and how a genetic disease might manifest itself. Many, if not most, diseases have a range of outcomes, from essentially no effect to devastating illness and, sometimes, death. Should you not marry someone when the genetic disease in questions might be so mild that it would never be noticed ? As more genes are added to the list, some people will run the risk of being "genetic wallflowers", rejected by every suitor because of the recessive genes they carry.