Mollie can get tested to see if she carries the CF mutation. If she does, then when she gets pregnant they can have the fetus tested to make sure it does not have two CF genes and is therefore free of the disease. Mollie would prefer simply not knowing what the risks are. She figures that once a baby is in their arms, they will be glad they had it, no matter what. This surprised and happy cry used to greet the birth of every child.
Many parents already know the sex of their child before it is born, through prenatal testing.
For most parents, learning the sex is just a bonus piece of information. The main reason they had the testing done was to learn whether the fetus had any genetic problems. Prenatal testing is most often done when there is a risk for a disorder. Any baby could end up with a genetic disorder caused by a new mutation. However, babies who have a disorder in their family tree face an extra risk of inheriting that disorder.