- A single pregnant woman in an abusive relationship with her baby's father persuaded him to waive parental rights so she could move away and marry another man who loved her and wanted to adopt her baby. When the girl was 7, she was diagnosed with a rare illness. Her doctor needed to know whether her biological father carried the gene mutations that could account for her condition.
- When his beloved uncle died with no heirs, a young man's mother inadvertently let the cat out of the bag - the man her son thought was his uncle was, in fact, his biological father. If that were found to be true, was he entitled to the man's Social Security or veteran's benefits or even an inheritance?
- A young man learned his girlfriend, who had broken up with him several months earlier, was due to deliver a baby any day. He needed to know if he was the baby's father so he could assume his parental responsibilities.
These seemingly diverse situations share a single and simple resolution: DNA matching. DNA, a substance in human cells that carries a person's genetic code, is passed down from parents to their children through generations. DNA determines eye and hair color, facial features, susceptibility to diseases, ear shape, the ability to roll their tongue or wiggle their ears, and millions of other traits. The similarity of DNA in blood relatives explains family resemblance ("You have your mother's eyes" or "You have your father's stubborn streak!"), and, more importantly, enables humans to learn to whom they are biologically related.
Paternity - or parentage - testing uses DNA to establish whether a man is the father of a child. Paternity testing based on curiosity can be done at home with reliable results using a $99 kit. For example, if two rivals for the love of a woman want to know who can take credit for her just-revealed pregnancy, a do-it-yourself paternity test should suffice.
If paternity testing is ordered by the court, however, the process must be more tightly monitored. Borrowing a phrase from law enforcement, the "chain of custody" must be controlled at every step of the process - from sample-taking in the lab to packaging and shipping it to the testing site to returning it to its final destination - to ensure there is no tampering or contamination. Court-ordered paternity testing may be sought to determine if a single mother is eligible for state assistance programs; which man is responsible for child support; and to whose Social Security and veteran's benefits the offspring is entitled.
DNA for paternity testing can be obtained from the man's blood taken via a finger-prick; or his saliva, usually taken from inside his cheek with a cotton swab.
There are two more non-invasive but less-frequently used methods for gathering DNA: from the mother's blood obtained about 12 weeks into her pregnancy and from umbilical cord blood at the time of delivery.
Two other methods of paternity testing - amniocentesis and Chorionic Villus Sampling - are accurate but rarely used because they are invasive and present risks to the fetus.
Many legal experts believe that when unmarried adults produce a child, paternity should be established immediately, and that legal counsel be promptly obtained to determine the steps that follow the determination of paternity.