If your and your spouse's ancestors are from Africa or the Mediterranean basin (as people corrected me above), there is a greater chance that your offspring will have certain diseases. If you meet the above criteria and your child has certain disease symptoms, you might want to spend resources to diagnose certain diseases that you wouldn't check for if your ancestors were, say, Chinese. Are you saying that we should throw out this information instead, out of principle? Should we start screening Chinese people for sickle cell?