Medical genetics has moved from the study of rare conditions to the illumination of disorders that impact the entire spectrum of medical practice. While there have been a number of predictions and concerns about this impact, this article examines three areas where medical genetics is clearly an important tool in medical practice. First, a family history aids in risk assessment, even in common disorders that are multifactorial. Second, by elucidating molecular pathways, gene identification may lead to the development of more efficacious medications that have fewer side effects. Third, an awareness of population-based risk and the availability of genetic screening in these populations will help physicians assess an individual patient's risk. To fully benefit from genetically based medical approaches, physicians will need to master a new set of principles and clinical skills. However, genetics has traditionally been taught as a basic science, sometimes under the purview of cell biology or biochemistry. Often, then, genetics has little or no place in clinical teaching. This article describes an effort at Harvard Medical School to integrate genetics into both the preclinical and the clinical curricula. The author looks at the underlying pedagogy, how basic science teaching in genetics is provided, and an approach currently being used to include genetics in clinical teaching.