The identification and cloning of many important disease-causing human genes have allowed the development of probes for detecting disease-causing mutations. Prenatal testing is already available for many genetic disorders. Additionally, presymptomatic genetic tests for adults and children are available for an increasing number of disorders. A number of genetic tests are offered directly to consumers, without requiring the participation of a health-care provider. Usually offered on the Internet, these direct-to-consumer genetic tests are available for a large and growing array of genetic conditions, everything from single-gene disorders such as cystic fibrosis to multifactorial conditions such as obesity, cardiovascular disease, athletic performance, and predisposition to nicotine addiction. A number of concerns have been raised about direct-to-consumer genetic testing, including concerns that some tests are offered without appropriate information and genetic counseling and that many consumers are not equipped to interpret the results. In 2013, the U.S. Food and Drug Administration prohibited the sale of direct-to-consumer genetic tests for the diagnosis of medical conditions.