New screening techniques and diagnostic tests for genetic diseases available for newborn screening can provide information about many diseases long before they are clinically detected. However, this information creates complex questions and ethical dilemmas regarding which newborns should be tested, when testing should occur, availability and costs of tests, and how families should be counseled. There is no national policy regarding newborn screening, which leads to great variation among states' newborn screening programs. This article reviews newborn genetic testing and provides a blueprint for clinicians to improve practice by incorporating into their care knowledge of new developments in newborn testing and screening.