As of 2002 more than ten thousand genes have been discovered, and it is estimated that 30,000 to 70,000 human genes will be identified as a result of the Human Genome Project over the following few years. Tests for more than 600 gene variants are already available in medical practice.

Genetic variants, or polymorphisms, are a normal part of genetic viability that may or may not be associated with an increase or decrease in disease risk. With advances in biotechnology, newly characterized genetic variants are being identified at a rapid rate. The challenge will be to ensure the appropriate use of genetic information to improve health and prevent disease in individuals, families, and communities.

The broad mission of public health is to act in society's interest to assure conditions in which people can be healthy. Public health genetics is the application of advances in...