Your Guide to Paternity Testing Staff
 Paternity DNA testing
If you're looking into a paternity test, we have your guide. Here's all you need to know about how paternity testing works, what types of paternity tests there are, and how to choose the best paternity test.

Paternity testing is all over the place now, from ads on the subway to daytime TV shows and, inevitably, hundreds of celebrities have been using them. Here’s our comprehensive guide to all you need to know about how paternity testing works, who can use it, prenatal paternity testing, and how to choose a paternity test for yourself.

How Do Paternity Tests Work?

The basics of paternity tests are pretty well-known. Each child gets half of his/her genetic information from his/her mother and half from his/her father. By taking a sample of the child's DNA and comparing it to both the mother's and the father's DNA, scientists can see if it matches. If the child has sections to his/her DNA which don't match either the mother or the father, then you’ve got the wrong daddy.

Cheek swab paternity tests work using Polymerase Chain Reaction (PCR), which multiplies the tiny sample of DNA from the swab billions of times (that's how they can get a reliable answer from just a dab of saliva). Lab scientists then take just 16 specific DNA fragments from the sample, of which 8 should match the mother's DNA, and 8 should match the father’s.

Paternity tests usually take a few days to process and return an answer, but if you’re in a hurry and need a definite answer ASAP for legal reasons or to fill in the name on a birth certificate, or for any other reason, then you can get an expedited test for results in just one day.

What Types of Paternity Test Are There?

Paternity tests used to work by comparing blood samples and checking that the child’s blood type matches his/her father’s, but this was not a fully reliable method. In the 1980s, DNA testing came in and proved 99.99% accurate. At first, you needed to send in a blood sample from all 3 people, which wasn’t so pleasant for anyone involved! Now, you can do a quick cheek swab to get enough genetic material for a paternity test that will stand up in court.

Today, there are a few types of DNA paternity testing. You can learn about prenatal paternity testing below. Postnatal paternity testing is done using a buccal cheek swab. There’s nothing painful about it; you just dab a cotton bud onto the inside of your cheek to gather DNA material, then seal it in a plastic bag. Do the same for the child and the possible father and send it off.

There's also an option to test for paternity using the umbilical cord blood immediately after birth. The hospital can take a sample from the umbilical at the time of delivery, or you can ask for a sample of the cord blood that's collected and kept in hospital. This type of paternity testing is every bit as accurate as a cheek swab.

Who Can Use Paternity Tests?

  • Some states require an unmarried mother to get a paternity test in order to know who the father is for legal purposes.

  • Both women and men have a legal right to request a paternity test in order to prove fatherhood. If the mother or possible father refuses, the case can go to court for a paternity hearing, and the whole process takes a lot longer.

  • A child can also get a paternity test. This happens most often with children who were adopted or who grew up without a father and want to learn for certain who their father is. Legally, anyone can request that the person they suspect to be their father take a paternity test, but different states have different rules about whether the possible father has to agree.

  • If a child has a legal guardian, then the guardian also has the right to ask for a paternity test for the child, even if the guardian isn’t a biological relative.

How Does Prenatal Paternity Testing Work?

As well as using a cheek swab paternity test after the baby is born, there are a few options for prenatal paternity testing. The type that’s most recommended is the state-of-the-art Non-Invasive Prenatal Paternity (NIPP) test. A blood sample is taken from the mother and the possible father. Using highly advanced technology, the DNA of the baby is isolated within the mother’s blood sample and compared against the DNA of both potential parents. It’s 99.99% reliable and can be done from the 8th week of pregnancy.

Another option is Chorionic Villus Sampling (CVS). This is done by inserting a tiny tube into the womb via the vagina and cervix to capture a sample of chorionic villus from the wall of the uterus. The villus shares the same DNA profile as the fetus, so it can be analyzed for DNA testing against the possible father’s DNA sample. CVS is extremely reliable and can be done from the 10th-13th week of pregnancy, but it’s not recommended for this purpose as it does carry a risk of miscarriage.

Amniocentesis can be done during the second trimester of pregnancy, but like CVS, it raises the risk of miscarriage. Amniocentesis draws a sample of the amniotic fluid from around the fetus for testing for paternity and genetic diseases. A doctor’s permission is needed to do both a CVS and an amniocentesis. If you need to do one of these tests to check for genetic diseases, then testing for paternity at the same time makes sense, but it’s best to use the NIPP or to wait until after the birth if you’re merely curious.

How Do You Choose the Right Paternity Test?

Choosing the best paternity test from the dozens that are out there mostly comes down to what you’re looking for.

If you need a paternity test to establish fatherhood for a legal issue like child support, custody, or immigration, then it’s important to use a court admissible test like one from Who’z the Daddy, International Biosciences, or Home DNA paternity test. These tests use samples collected in sterile conditions in a lab to be sure that there’s no contamination and are carried out according to internationally agreed upon standards. In this case, the most important factor might be which company has a lab closest to you.

People who are curious about their ancestry may want to spend less money and use a home paternity test. This is where you collect the samples at home and send them in to be analyzed. The results are still 99.99% reliable and have a lower price tag, but you can't use them as evidence in court. MyHeritage offers to help you find your family through DNA testing. Many companies that offer court-admissible tests also have less expensive peace of mind home testing kits. You can even pick up home DNA test in most pharmacies.

If you need prenatal paternity testing, you’ll have to choose a service that offers prenatal tests. homeDNAdirect, International Biosciences, and Who’zTheDaddy? all include prenatal testing, but you might have to go with the one that your hospital or doctor approves.

Here are the main things to consider when choosing the right paternity test:

  • If the test is needed for legal purposes, make sure that it's court-admissible and carried out under sterile conditions

  • Approved and accredited by the AABB international professional standards group, or the ISO 17025 accreditation (or both)

  • Whether the company has labs near to you and/or the alleged father to easily collect sterile samples

  • Experienced staff

  • The confidentiality and privacy policy (for example, if you don’t want your child to be able to access the results without your agreement when he/she reaches adulthood)

  • Speed of processing samples if you need an answer urgently

  • Cost

  • Which prenatal paternity tests are available, if relevant, and whether your doctor approves the process


Today, paternity testing is easy, fast, and inexpensive so there’s no reason why anyone should carry unresolved doubts about their parentage. Choosing the right paternity test is simple, so now you can pick up a DNA test and learn the truth anytime. Staff's editorial staff is a professional team of editors, writers and experts with dozens of years of experience covering consumer, financial and business products and services.