A new model for care of children with genetic disorders has emerged from the pediatric and genetic communities in the last decade. This strategy incorporates the basic principles of well-child care, including ongoing psychological support for families, health screening, and prevention, into health supervision visits for children with these conditions. The same types of guidelines that have been developed for well children can also be applied to the routine follow-up and screening of children with these special health care needs. A number of general issues are applicable in the discussion of health supervision guidelines: correct diagnosis, analysis of the natural history of the condition, critical review of screening modalities and interventions, ongoing psychological support, and genetic counseling. With these points in mind and after a thorough review of the natural history of a disorder, guidelines can be developed and often applied to the primary care setting. Down syndrome is an ideal condition to which one can apply such a model because most children are cared for by primary care pediatricians, and the natural history is relatively well studied. Discussion of health provision in Down syndrome brings out some of the controversies regarding routine screening and review of interventions. Discussion of the natural history and uncertainties evident in the care of infants with trisomy 18 exemplifies the important issue of ongoing psychological support. Review of the natural history of neurofibromatosis emphasizes all of the principles involved in providing this model as a framework for health supervision. One of the key identified but unresolved issues is the decision as to when a primary care pediatrician can orchestrate the care on his or her own versus referral to a multidisciplinary team of specialists. In some conditions such as Down syndrome, it seems obvious that the primary care pediatrician can manage most of the care with periodic and appropriate referral to the necessary specialists. On the other hand, children with cystic fibrosis, meningomyelocele, and craniofacial syndromes almost always need referral to the specialist team because of the rarity of the disorder and the complex number of specialists involved in management. A condition such as NF-1 falls somewhere in between. Most children can be cared for in their childhood years by the pediatrician with referral when a symptom or sign emerges, but others would argue that all children with NF-1 need to be seen by a multidisciplinary team.(ABSTRACT TRUNCATED AT 400 WORDS)