In the last decade, DNA testing has gone from an expensive procedure (available only to law enforcement and professional scientists) to a routine practice that is widely available — more than 250,000 paternity tests were performed in the United States alone in 2009. Paternity tests are being used by lawyers who need to establish (or disprove) who is the father of a child, by adopted or artificially-conceived children who want to find their birth parents, and by individuals interested in their heritage or health risks passed on by an unknown parent. Because of this, many men have been asking their doctors about how accurate are paternity tests, and the answers are surprising.

How accurate are paternity tests? They are extremely reliable. It works by taking two DNA samples, one from a parent and one from a child, and examining their genes to see if a statistically improbable number of pairs match up. These tests are more reliable in identifying fathers than mothers because of the DNA used in the test. In cases where children are being matched to a male parent, paternity tests are more than 99.9999% reliable — meaning for every 100,000 tests performed there is only one error.

Some people have asked, “How accurate are paternity tests if there are problems during testing?” The reliability of paternity tests depends on the quality and legitimacy of the DNA being collected. The most common method is through a simple cheek swab, where cells are collected from a inside a client’s mouth with a cotton swab, but DNA can also be matched through semen, hair, or skin cells. The largest source of unreliable tests is illegitimate DNA — a client has not submitted his or her own DNA, and instead substituted a sample from another person. Such substitutions eliminate the validity of the paternity test.

The cost of DNA testing has declined almost ten-fold in the last decade, making it an affordable way to conclusively establish the paternity of a child. These tests are available at most health care providers and even through online services, which can perform the test in as little as ten minutes and have results to a client within 4-6 weeks. If wondering “How accurate are paternity tests?” has kept you from getting a test, there should be no reason to worry any longer!