 The American College of Obstetricians and Gynecologists recommends all people thinking of becoming pregnant be tested to see if they are a carrier.Because development of CF in the fetus requires each parent to pass on a mutated copy of the "CFTR" gene and because CF testing is expensive, testing is often performed initially on one parent.If testing shows that parent is a "CFTR" gene mutation carrier, the other parent is tested to calculate the risk that their children will have CF.