Despite the potential of expanded newborn screening for biochemical genetic disorders as a significant advanced in preventive medicine, there are serious concerns about its social, ethical and legal implications. These concerns apply to identification of he disorders as well as to the false positive results that occur. The arguments for and against expanded screening generally are related to the medical issues, the ways in which parents will respond to the information and how the child will be perceived by society. With technology, particularly tandem mass spectrometry (MS-MS), as a driving force, there is the possibility of expanding screening for an even larger number of genetic disorders. It is important to study the ethical, social and legal implications of these programs now when they are new and still amenable to change. The aims of this study are to: 1) compare newborn identification of biochemical genetic disorders by expanded screening with clinical identification in term of the interaction between the parents and the health care system and elements of health outcome for the child and family and; 2) assess the impact of false positive identification in expanded newborn screening in terms of parental response and interactions with the health care system. This is a 3-year prospective study limited to the disorders that have been recently added to the newborn screening list in Massachusetts. For aim 1, parents of newborn infants diagnosed through MS-MS in Massachusetts and Pennsylvania (where such screening has been instituted) will be compared to parents of children diagnosed with the same metabolic disorders in the New England states where expanded newborn screening has not been adopted. Six months after the diagnosis is made and 1 year later, the mothers and fathers will be interviewed separately. For aim 2, parents of infants initially screened false positive for one of the biochemical genetic disorders will participate in a phone survey. A sample of parents of infants screened normal will also be included. When the infants are 6 months old, their parents will be interviewed about their knowledge of newborn screening, their response to the information they received and their satisfaction with the newborn screening process.