Testing for the Gene What? -test to identify who carries the gene Why? -CF gene is recessive -people can carry the gene but not have CF -parents can pass the gene to their children Results: -test prospective parents -carriers can decide not to have children		Scientists have designed a test to identify people who carry the cystic fibrosis gene. The test is based on knowing where the gene is located. The CF gene is a recessive gene. This means a person can carry one copy of the gene and still not be affected by the disease. However, if this person has children with another person who carries the CF gene, there is a 25 per cent chance that their children will inherit two copies of the gene and suffer from the disease. The test identifies whether prospective parents carry the defective CF gene. If they do, couples then decide whether to have children or not.