The rare genetic condition that creates problems with DNA testing

If you’re a regular reader of our blog then you know how important it is for fathers to establish paternity here in Massachusetts. Not only does it create a legal link between father and child — which is helpful is custody and support cases — it also makes it easier to get answers about a child’s medical history and if they are eligible for additional benefits because of their father’s history.

If you read our February post on paternity, you know that there are two main ways in which to establish paternity: signing an acknowledgment of paternity form and through DNA testing. It’s the latter of these two methods that we’d like to look at in today’s post though because in some cases, it can actually create complicated legal issues.

Most people believe that DNA testing is infallible. In paternity cases, we trust that the test results are accurate. Hardly ever do we question their validity. But did you know that there is a rare genetic condition that can turn paternity testing on its head? Called chimerism, this quirk in genetics can actually create complex legal situations for parents, requiring extensive help from an attorney and medical professionals alike.

Considered to be a rare condition, chimerism is believed to occur when two eggs, fertilized with two different sets of DNA, converge during development to create a single person. While visible indicators such as patches of differently colored skin can indicate a chimera, a person might still be a chimera without visible indicators. This might only become apparent though after extensive DNA testing all over the body.

Take for example the case of Lydia Fairchild who, in 2002, faced overwhelming accusations that she was not the mother of her three children after DNA testing could prove no link between herself and her children. It wasn’t until prosecutors learned about chimerism and after extensive DNA testing of tissues from all over Fairchild’s body that they eventually confirmed that she was the mother.

Because chimeras have two sets of DNA in their bodies, it’s easy to see why this could create legal problems for parents all over Massachusetts and the nation. Though it may not be the first thing courts think of in paternity cases, it should be something to consider, especially because it could cost someone their right to see their children later on.

Sources: Psychology Today, “The You in Me,” Sam Kean, March 11, 2013

The National Center for Biotechnology Information, “A mythical beast. Increased attention highlights the hidden wonders of chimeras,” Howard Wolinsky, March 2007