This background review has attempted to pinpoint problems and issues of intervention strategies to promote health among children. Some traditional interventions as they are now provided in preventive service packages, for example, are critically assessed; new interventions like neonatal intensive care, prenatal diagnosis, periconceptional vitamin supplementation, and nutritional supplementation during later pregnancy are welcome; supportive outreach services through nurse home visitors to bring proved technologies to those in greatest need, while they may not be new have shown renewed effectiveness. Recently recognized problems like the "new morbidity," and newly recognized prevention potentials like the great prospects for accident prevention, adequate school health programs, and special adolescent care programs are promising areas for preventive services effectiveness. We do not claim that a comprehensive list has been presented. Rather, an attempt has been made to challenge some traditional preventive techniques, e.g., preoperative x-rays, to stimulate thinking about new organizational forms of care delivery, and to keep an open agenda. As a result, the reader will feel a "lack of closure"--challenges without definitive answers. The general assertion is that personal preventive care is only weakly related to health and that preventive care delivery is not a simple technical problem. Let me summarize the main points. First, the lack of evidence and comprehensiveness. Other reviews of preventive care packages could have been discussed. The presentation by Fielding [164] in the Institute of Medicine's background papers to Healthy People also includes service listings for pregnant women, normal infants, preschool children, schoolchildren, and adolescents. The Lifetime Health-Monitoring program by Breslow and Somers [165] set goals and services that have already become practice patterns for large parts of the country. Many more cost-effectiveness studies of immunizations and screenings could have been cited. The point, however, is not whether technologies with the potential for prevention exist, but whether these technologies have been used and are now used effectively for that purpose, and whether their performance in the real world represents the best use of scarce and expensive resources. Scientific evidence of organized delivery effectiveness is rare.(ABSTRACT TRUNCATED AT 400 WORDS)