Are prenatal and preimplantation diagnosis equally effective for disease transmission prevention?

Prenatal (PD) or preimplantation diagnosis (PGD) can be performed to prevent transmission of a given genetic disease in the case of affected or carrier couples without having to give up biological motherhood or fatherhood. Affected couples have a high risk of bearing affected children, but they can also bear healthy children in a completely natural way. Prenatal diagnosis can be performed to find out if the future baby will be healthy or affected. In other words, once pregnancy has been achieved naturally, the baby’s DNA can be tested by means of amniocentesis or a chorion biopsy to find out if it is healthy or affected. In the latter case, pregnancy should be interrupted to prevent the birth of an affected baby. Yet, this information can be found by means of PGD before the embryo is transferred into the mother’s uterus. This way, gestation of affected babies is avoided and pregnancy interruption is not necessary.