Can a DNA test prove Paternity or Maternity

Genetic testing has been used to confirm parenthood for decades.

Long before the technology that powers 23andMe was developed, DNA-based methods – perfected in the 1970s and ’80s – were already able to prove paternity with an accuracy reaching 99%.

There are many reasons to confirm parenthood, from adoption, immigration, child support, or simple proof. Can a DNA test prove paternity or maternity? They most certainly can – some modern methods can confirm fatherhood before the baby is even born. There are some things to keep in mind before embarking on this journey; education and consideration are strongly encouraged before using a DNA test to prove paternity.

A brief history of paternity testing

The concept of paternity testing dates back to the 1920s. Even Charlie Chaplin mobilized the process in 1943 when he was accused of illegitimately fathering a child. The test definitively excluded him from possibly being the father, but the courts were wary of the new technology. While he ended up paying child support nonetheless, the high-profile case spurred new laws and regulations on paternity testing.

These old methods don’t investigate DNA sequences or variations directly. But, they still rely on the general concepts of Mendelian inheritance laid down in 1865. While Gregor Mendel demonstrated the passage of traits from one generation to the next, there are only a small number of traits that are known to be inherited reliably from either parent. 

One of these is your ABO blood type, denoting the molecular flags carried by your blood cells. Two ‘O’ parents can only produce ‘O’ children, while two ‘B’ parents can create either an ‘O’ or ‘B’ child. To either set of parents, a child with ‘A’ or ‘AB’ blood type would be impossible.

The ABO blood type test – along with many similar procedures that came after it – operate on the opposite premise from our goal. They don’t have any capacity to prove paternity or maternity, but they can exclude suspected parents from consideration. However, these tests have a significant shortcoming: only 30-40% of the population can be reliably excluded – depending on blood type – but no closer to confirming a single individual.

Modern DNA testing to prove parenthood

Modern paternity testing is based on DNA analysis – just a different form of an at-home genetic test. Some aspects make these tests unique from the likes of Ancestry and LivingDNA. Mass-market genealogy services aim to cast the widest net possible, giving you a multitude of results at the expense of some confidence in the outcomes. Kits that are marketed explicitly as paternity tests use a modified but streamlined process that maximizes confidence and accuracy.

Oddly enough, testing for parenthood usually only analyzes a few dozen DNA locations to formulate their reports – compared to the hundreds of thousands that are scanned by companies like 23andMe. These few genetic markers are incredibly accurate in predicting the one thing that matters most: confirming parenthood. Even a quick search in your neighborhood Walgreens can net at least two tests that prove paternity with an accuracy of over 99.99%.

Can a DNA test prove paternity?

Such DNA paternity tests require a sample from both the child and the suspected parent. Some allow for a third sample to increase accuracy – either from the mother or another confirmed relative. In this way, a DNA test can prove paternity definitively and accurately. Unfortunately, these results are often not legally recognized, but some services offer addition steps to meet that standard.

In cases where you can’t obtain a sample from a suspected parent, you still have some options. DNA testing kits from Ancestry, MyHeritage, LivingDNA, and 23andMe have vast databases of potential relatives. For more information, see our guide Can a DNA test help me find relatives? And familiarize yourself with The Pros and Cons of genetic testing before diving into these wide-ranging tests.