Like HowStuffWorks on Facebook!

What can your spit tell you about your DNA?


Genetic Testing Laws
Monsignor Rino Fisichella, who heads the Pontifical Academy for Life, gestures during a press conference at the Vatican on Feb. 17, 2009. The Vatican is warning of the "relentless'' spread of a eugenics mentality with the advance of genetic testing.
Monsignor Rino Fisichella, who heads the Pontifical Academy for Life, gestures during a press conference at the Vatican on Feb. 17, 2009. The Vatican is warning of the "relentless'' spread of a eugenics mentality with the advance of genetic testing.
­AP Photo/Andrew Medichini

­Some people char­acterize at-home genetic testing as a revolution in health care. Others are more cautious. A few are deeply troubled. Much of the concern centers on the uncertainty of results that come back from the testing companies.

Having a genetic marker for a disease is not a guarantee that a person will actually get that disease. Few conditions are purely genetic. Most have both inherited and environmental causes. Many cancers, for example, require a genetic predisposition, as well as an environmental trigger to set the disease in motion. As a result, consumers who make decisions based solely on the results of a genetic test may receive unnecessary treatment or make unnecessary lifestyle changes.

A few states require consumers to obtain authorization from a health care provider before they undergo genetic testing. Some states prohibit at-home testing altogether. Currently, 25 states and the District of Columbia permit at-home genetic testing without restriction [source: Genetics and Public Policy Center]. The U.S. Food and Drug Administration doesn't regulate direct-to-consumer tests, although the labs themselves must comply with the Clinical Laboratory Improvement Amendments (CLIA), which ensure quality laboratory testing. CLIA doesn't, however, require genetic testing labs to enroll in programs designed to assess their analytic validity -- their ability to deliver correct answers when performing tests.

Finally, there's the issue of genetic discrimination. Many people worry that their genetic information will interfere with their ability to get insurance coverage. In May 2008, the Bush administration took one major step to prevent this by passing the Genetic Information Nondiscrimination Act, or GINA. GINA protects Americans by making it illegal to use genetic information to influence health insurance and employment decisions. It does not extend to genetic information-based discrimination in life or long-term care insurance.

So before you spit into a cup and send it off for testing, you had better make sure you're fully prepared for all consequences, good and bad. Perhaps it's best to remember an old proverb that warns, "Don't spit into the well -- you might drink from it later."