Scientific findings on the genetic underpinnings of disease have greatly expanded over the last decade, leading to many new genetic tests. Once confined to rare genetic disorders and prenatal testing, genetic tests can now estimate susceptibility to breast cancer, hereditary colon cancer, and Alzheimer’s disease. With the recent advent of direct-to-consumer genetic testing, people can order medical and nonmedical tests, including genome scans and DNA analyses that claim to identify ancestry, often over the Internet.

A longstanding concern about genetic testing is discrimination—that people found to be at increased risk of a serious condition could be denied health insurance or employment or face other forms of bias. The federal Genetic Information Nondiscrimination Act (GINA), passed in 2008, prohibits such discrimination. But there are many other unresolved ethical and legal issues.