As far back in the history of medicine as Hippocrates, astute clinicians have observed that one's family history influences disease risk. Although collecting information on the disease status of relatives has long been a fixed part of the medical interview, only over the past few decades has medical science begun to unravel the genetic underpinnings of the family history. This discussion describes the genetic information obtainable from the family interview, comments on how this information influences health care, and discusses the limitations of the family history interview for disease risk assessment. For some chronic diseases and cancers, individuals with positive family histories often have lifetime disease risks that are two- to fourfold greater than the general population. As such, multiple clinical guidelines for disease prevention ...