Genetic testing and prenatal diagnosis

The ability to detect prenatally all major chromosomal aberrations and many disease-genes has been a tremendous aid to genetic counselling. Knowledge of the fetal genotype is useful primarily in making reproductive decisions. If a disorder is diagnosed early in pregnancy, the couple has the opportunity of aborting the fetus and beginning again. Fortunately, in about 97% of prenatal analyses, the fetus is found not to have the disorder in question. This findings relieves anxiety for the parents, who can then anticipate a newborn no more at risk for abnormality than a random birth. Many couples at substantial risk of having a child with a serious defect would refrain from further pregnancies unless assured that the risk could be reduced. Thus, because of the availability of fetal diagnosis, life is given to children who would otherwise never be conceived.