There are some 20,000 genetic diseases. One in 10 babies born now has a genetic disability. The more healthier human beings are born, the less problems society will have. The severely retarded, those born with severe physical disabilities and genetic diseases should not be born, but aborted before the fourth month.
Science has taught us the importance of genetics within the human body, and even within other animals. For humans, having certain genetics can make them predisposed towards a great likelihood of congenital diseases or acquired diseases. When these people have children, there is a chance that those genes are passed on. For this reason genetic screening has a basis in science.
There are certainly precedents set along the lines of genetic screening. At this point in time, if a fatal disability - either for the baby or mother - is found during pregnancy, women are offered the option of terminating their pregnancies, even past typical weeks for abortions, a very controversial subject. It is not yet commonplace to test fetuses for a very wide variety of identifiable traits, but science is slowly uncovering options.