Previous studies of genetic counseling have mainly focused on outcomes defined by researchers or service providers, and have frequently related to changes in reproductive behavior and/or client knowledge. A longitudinal study of 43 families referred to a clinical genetic service was undertaken to ascertain client needs and expectations of the service, and to identify relevant outcomes from the clients' perspective. Semistructured interviews were conducted with each client, prior to and after genetic counseling. The transcribed interviews were analyzed using grounded theory. The need for certainty emerged as a powerful factor that motivated clients to pursue the genetic referral. The client's lay knowledge of the condition, satisfaction of the need for certainty, and the formation of a personalized relationship between the client and the genetics staff significantly influenced the central outcome, identified as a change in the client's psychological adaptation to the genetic condition in the family.