Many people when they think of prenatal testing mean or certainly think about testing that's done during the pregnancy, and that is one type of prenatal testing. there's other kind of truly prenatal testing that is what's sometimes called preimplantation genetic diagnosis when you take a fertilized egg very early in the process and using artificial reproductive means before it's even been implanted in the uterus to be able to select for certain genetic aspects of the of that embryo. 