ABSTRACT.Objective. Traditional population screening focuses on conditions for which early treatment prevents severe morbidity and mortality. The classic example in pediatrics is newborn screening for phenylketonuria, which began in the 1960s. In 1968, Wilson and Jungner delineated 10 criteria that would justify population screening. These criteria have been reaffirmed by many newborn screening task forces as the standard for adding conditions to newborn screening programs. Today, however, some newborn screening programs are expanding to include conditions that may not meet all of the traditional screening criteria. Little is known about pediatricians' attitudes toward expanding screening. We examine the attitudes of pediatricians and pediatric subspecialists toward screening for cystic fibrosis (CF), Duchenne muscular dystrophy (DMD), fragile X, and type 1 diabetes.Methods. A cross-sectional survey was conducted of 600 pediatricians, including those who are members of the section of genetics, endocrinology, pulmonology, and neurology of the American Academy of Pediatrics. For each condition, pediatricians were queried about (1) testing high-risk infants, (2) newborn screening, and (3) population screening or testing beyond the newborn period. Demographic data were also collected.Results. A total of 232 (43%) of 537 eligible pediatricians returned surveys. More than 75% support testing high-risk infants for all conditions except type 1 diabetes. CF was the only condition for which >50% supported newborn screening. Newborn screening was preferred over screening older infants for all conditions except fragile X. Subspecialty affiliation did not have a significant impact with respect to attitudes about testing highrisk children, newborn screening, or screening beyond infancy. We analyzed the data by the number of patients with the queried condition under the physician's care and by the number of affected family members. Neither aspect was significant. We also analyzed the data by gender, by year of residency graduation, and by geographic location. None of these factors revealed significant differences in responses. For each condition, 8% to 41% of physicians would personally choose to test their own infant. We found that physicians' opinion about what they would want for their own children correlated with their attitude about population newborn screening. Those who would personally choose testing of their own infants were highly likely to support newborn screening for CF (98%), DMD (94%), and fragile X (98%), but only 78% of those who would personally opt for newborn screening of type 1 diabetes would also endorse population-based screening. This was statistically significant for each condition. Those who would choose not to test their own infants were significantly less likely to support newborn screening of the general population. T raditional population screening focuses on conditions for which early treatment prevents severe morbidity and mortality. The classic example in pediatrics is newborn screening for phe...