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Paternity Test

While most pregnancies are welcome, if occasionally surprising events, not every woman is prepared for the news that she is pregnant. A woman who receives this news at a time when she has recently had sex with more than one male partner may find herself in an awkward position, and asking an awkward question—who’s the father of my baby? A paternity test is the only reliable way to answer that question.

Why is Paternity Testing Sometimes Necessary?

More than 50 percent of all new mothers under the age of 30 are not married (although many of them are in committed partnerships). As prevailing attitudes toward sex have changed in recent decades, monogamy, while still the norm, is not nearly so universal as it once was. And of course, for as long as marriage has existed in human society, there have been extramarital affairs—some of which result in unplanned pregnancies.

How Does a Paternity Test Work?

Until about thirty years ago, the only scientific paternity test available involved blood typing. This was helpful for ruling out paternity in some cases—if a woman had blood type O and her baby had blood type B, then a man with type A blood could be ruled out as a possible father—but it could not conclusively prove paternity.

The advent of DNA testing in the 1980s changed all that. Given blood samples from the mother, the baby, and the possible father, paternity could be determined with 99.99% accuracy. In the 1990s, tests were developed that required only cheek swabs, which collected what are known as buccal cells; these tests eliminated the need for blood collection.

In recent years, advances in DNA testing have made it possible to obtain reliable results from the potential paternal grandparents, or even from cousins. This is sometimes useful in cases in which the potential father is unwilling to cooperate by providing a sample of his own DNA.

In Utero Paternity Testing

In some cases it may be necessary for legal reasons to determine paternity before the baby is born—for example, in order to assess a potential father’s financial responsibility for the mother’s prenatal medical care. One way of doing this is with what is called invasive testing, such as amniocenteses or chorionic villus sampling (CVS). CVS testing, which is only done between the 11th and 13th weeks of pregnancy, involves taking a tissue sample from the placenta. Many medical care providers are reluctant to use these methods for paternity testing, however, due to the slight risk of miscarriage associated with them (this risk is 1% for CVS, 0.5% for amniocenteses).

Fortunately, less invasive blood tests have been developed in recent years that can determine paternity as early as the eighth or ninth week of pregnancy. These tests work similarly to NIPT testing, which checks for possible birth defects such as Down syndrome by analyzing minute traces of fetal DNA that can be found in the mother’s blood. While these non-invasive blood tests do show considerable promise, they have not, as of this writing, been endorsed as accurate by the American Association of Blood Banks (see below).

Ensuring the Reliability of a Paternity Test

If you need a paternity test to determine who is (or may be) the father of your baby, you will need to find a laboratory that has been accredited by the AABB—the American Association of Blood Banks. The AABB is a non-profit organization that works with the Food and Drug Administration (FDA) to help regulate the nation’s blood supply. This accreditation is especially important if you intend to use the paternity test results in any court proceeding. A list of AABB-accredited labs can be found on AABB’s web site.

Home Paternity Tests

At-home paternity tests can be obtained online or at many pharmacies, but in order to get results you must mail the samples to a laboratory. While these home tests can be useful on a personal level, the results are not admissible in court. For paternity test results to be accepted in any legal proceeding, the testing must take place at an AABB-accredited lab, it must be witnessed by a third party, and photos and fingerprints must be taken at the time of the testing.

How Long Does it Take to Get the Results of a Paternity Test?

The results of buccal cell paternity testing (cheek swabs) are generally available within five to ten days from the time the laboratory receives the samples. Paternity testing using amniocentesis or CVS takes three to four weeks.

How Much Does Paternity Testing Cost?

Home paternity test kits can be found for under $100, but testing at an AABB-accredited lab costs over $500.

Medical References:

    The Cleveland Clinic https://my.clevelandclinic.org/health/diagnostics/hic-DNA-paternity-test The New York Times http://www.nytimes.com/2012/06/20/health/paternity-blood-tests-that-work-early-in-a-pregnancy.html?pagewanted=all&_r=0 The Science, Health and Environmental Reporting Program in the Arthur L. Carter Journalism Institute at New York University www.scienceline.org/2012/01/how-does-a-paternity-test-work/ American Association of Blood Banks www.aabb.org/
[Page updated December 2014]