One in every 100 Americans is born with a serious genetic disorder, and more will face a disease with genetic components in their lifetime. In the past decade, fledgling genetic science has identified more than 4,000 diseases connected to genetic factors. Genetic doctors and testing have become relatively common. But what is genetics'? How do these doctors and their tests work, and what if anything can they change? Dr. Scheuerle walks us through this new field and explains the basics, detailing diseases and disordes that can present in each life stage: in infancy and childhood, in puberty...