It is safe to predict that we are still at an early stage of newborn screening. There is a high probability that in the future, MS/MS or a similar technology will be applied to screening for many additional disorders, both metabolic and non-metabolic. The ability to examine DNA in the Guthrie specimen, currently used in second-tier screening, has opened up opportunities for primary screening of a huge array of potential disorders that previously could not be identified in the newborn. Among the possibilities under current discussion are type I diabetes, severe combined immunodeficiency, fragile X syndrome, hereditary hemochromatosis, and lymphoblastic leukemia. The major problems with these considerations, however, are that preventive treatment is not yet possible for most of these disorders, and for many, the abnormal finding determines only susceptibility for and not certainty of disease. Our experiences in the past with such newborn screening as that for histidinemia, which was found not to produce disease, and alpha 1-antitrypsin deficiency, which was not medically beneficial and had negative psychological effects, are lessons that must be taken seriously when considering new avenues of screening. Beyond further application to the Guthrie blood specimen and testing in a centralized laboratory is the broader concept of newborn screening exemplified by universal screening for hearing impairment. This screening is conducted directly on the newborn in the newborn nursery. This type of in-hospital universal screening may have wider application in the future. Much activity is underway to develop a consensus on appropriate newborn screening. This activity has been led by the Genetic Disease Branch of the federal Maternal and Child Health Bureau (MCHB), Health Resources and Services Administration (HRSA), in collaboration with the American Academy of Pediatrics and, currently, in collaboration with the American College of Medical Genetics through a committee to promulgate criteria for inclusion in newborn screening. The aphorism, "good judgment comes from experience, and experience comes from bad judgment," may be applied to newborn screening. Our challenge now is to use the experience we have from the previous bad judgements to guarantee future good judgements.