The discovery of DNA was a huge leap toward understanding heredity and the way our parents' biology directly influences our own since DNA is the ultimate "source code" of the human race. Since we get our genetic makeup directly from our parents (half from each parent), it is easy to determine whether a man is the biological father of a child based on the comparison of the two DNA samples.

DNA paternity tests are over 99.9% accurate. They can be done during pregnancy from the mother's blood as early as 8 weeks of the pregnancy.

Every human cell contains a copy of the entire DNA of the person, 50% of it comes from the mother and 50% from the baby's father. Given the samples of at least the child and an alleged father, DNA paternity tests are held to be 99.999% accurate.

Paternity testing before birth

If you have any questions about who the baby's father is then the most reliable paternity test method is testing for DNA which can be done as prenatal paternity testing — either during pregnancy or after delivery of the baby.

DNA stands for "deoxyribonucleic acid" which is a material present in nearly all living organisms as the main constituent of chromosomes, carriers of genetic information that are found in the nucleus of most living cells.

In the past, DNA-based paternity tests were only available after delivery from tissue or blood collected from the baby and the alleged father. Or invasive tests had to be done during pregnancy potentially risking the baby's life. It is now possible to do paternity testing during pregnancy and prior to birth with a simple non-invasive blood test from the mother and a DNA test from the father. This makes it possible to do fetal DNA testing from the mother's blood as early as 8-9 weeks in pregnancy without risk to the baby because only blood is collected from the mother without the need for an invasive test.

Since cells from the fetus float freely in the bloodstream of the pregnant mother as early as 8 weeks of the pregnancy, paternity testing companies can develop a DNA profile of the fetal cells and compare the profile to the DNA profile of the presumed father. A conclusive paternity test report can be delivered in as little as 3 business days after both DNA samples have been received, but the supposed father has to be tested too..

If the alleged father is unavailable or unwilling to do a paternity test, a grandparentage test or a test on the father's child can also be performed to provide some information This test uses the supposed father's parents' DNA to determine if the child is biologically related to the grandparents. This test determines if the child is a descendant of the grandparents, so if they had more than one son, all sons would be included as a potential father of the child.

DNA samples can be obtained in a variety of ways, including:

• blood
• cheek swab
• umbilical cord when the baby is born
• saliva
• semen
• hair
• another piece of tissue

There is the option for an invasive prenatal paternity test as well, although some of the invasive prenatal methods can sometimes pose some danger to the fetus and these procedures require the permission and help of an OB-GYN. The two main methods of invasive prenatal paternity tests are amniocentesis and chorionic villus sampling, or CVS, while there is an easy alternative to the non-invasive prenatal paternity test drone from the blood of the mother.

What happens at the paternity testing?

During the paternity testing appointment, all paperwork and consent forms need to be signed by all people involved in the paternity testing.  Consent forms need to be signed by all people involved in paternity testing. After the payment is taken, the paternity test will begin.

Depending on the type of paternity test being given, there could be different methods of cell harvesting. For cheek swabs, which are the most common and the least expensive, three swabs are taken from the inner cheek of the mother, father, and infant (called the trio).

These swabs are placed in sterile bags to await DNA extraction. After all, parties have finished the swabbing they are free to leave. 

At the earliest, the test can be completed in 3 days in most cases. Court-ordered paternity test results may only be sent to the court. In order to receive a copy of the paternity test, those involved will have to be in contact with the court systems. While the paternity test results take as little as three days, the paperwork involved in the court system may stretch out the announcement of the results to 6 months or more.

Invasive testing

The invasive tests come with certain risks to the baby, in cases where the paternity needs to be determined before the child is born, there are two invasive options for prenatal paternity testing - amniocentesis and CVS, and one on-invasive option, a blood test from the mother.

Amniocentesis 

Amniocentesis involves the doctor using an ultrasound to guide a needle through the abdomen into the uterus to get a sample of amniotic fluid, which contains the baby's genetic material.

After the 14th week of gestation, mothers can request an amniocentesis for paternity testing. The amniotic fluid carries the cells of the baby and these cells can be used to strip out the DNA needed for a paternal match. An amniocentesis can be done any time during pregnancy after 15 weeks, though most are done between 15 and 20 weeks.

Chorionic villi sampling (CVS)

During chorionic villi sampling (CVS) the doctor guides a needle up the vagina or through the mother's abdomen to collect pieces of tissue called chorionic villi off the walls of the uterus, which come from the fertilized egg and thus also have the baby's DNA.

CVS, or chorionic villus sampling, takes a small piece of the villa that formed during the beginning weeks of gestation, usually around 12-14 weeks, and tests that DNA for a paternity match. After the 14th week of gestation, the CVS test can no longer be completed as the villa deteriorates.

In utero paternity testing is expensive and may not be covered by medical insurance. There is also the risk of damage to the fetus or the amniotic sac. In rare cases, the fluid will continue to leak from the sac and the baby will need to be delivered or you have a miscarriage. Most often, the court system will need to be involved for a doctor to consent to prenatal paternity testing.

How much does paternity testing cost?

The cost of the paternity test will vary depending on the state where the test is run and the situation surrounding the paternity test. The general price range for a paternity test in an office ranges from $400 to $500. A test from the most established and trusted DNA paternity testing facility should not cost more than $550 .

If the paternity test is conducted as a result of a court order, the price may be lower than average as the court system may have established a contract for service with a specific DNA paternity testing facility. The ordered trio will need to contact the courts to find out if there is a contract of service in place for a specific lab. 

In rare cases where the first paternity test is inconclusive, a more rigorous test will need to be conducted to establish paternity. This test can cost much more than the average blood or cheek swab DNA paternity test.

The Ob-Gyn can also choose to order a paternity test while the fetus is still in utero. This test requires chorionic villus sampling or amniocentesis. These tests come with a very large price tag as the cost of the medical procedure will need to be covered along with the cost of the paternity test. Specific prices will vary depending on whether the insurance covers the medical procedure or not.

The final option for paternity testing is the at-home kit. This kit will give completely accurate results when the directions are followed. However, the kit results will not be admissible in a court of law.

Paternity information state by state

Paternity laws differ from one state to the other. Below is more information on paternity establishment for the US states:

• California court paternity information
• Texas AG paternity information 
• New York court paternity FAQs 
• Florida paternity information
• Illinois paternity information
• Pennsylvania paternity law
• Ohio state bar paternity information
• Michigan
• Georgia
• North Carolina
• New Jersey
• Virginia
• Washington
• Massachusetts
• Indiana
• Arizona
• Tennesse
• Missouri
• Maryland
• Wisconsin
• Minnesota
• Colorado
• Alabama
• South Carolina
• Louisiana
• Kentucky
• Oregon
• Oklahoma
• Connecticut
• Iowa
• Mississippi
• Arkansas
• Kansas
• Utah
• Nevada
• New Mexico 
• West Virginia
• Nebraska
• Idaho
• Hawaii 
• Maine
• New Hampshire
• Rhode Island
• Montana
• Delaware
• South Dakota
• Alaska
• North Dakota
• Vermont
• Washington, D. C.
• Wyoming

How accurate is paternity testing?

Paternity testing is used to establish the biological paternal parent of a child. Paternity testing, like any other test, is close to 100% accurate but not completely 100%.

There are results that cannot be contested in a court of law due to the overwhelming nature of the results. There are two forms of paternity testing results — exclusion and inclusion.

The exclusion paternity test can be considered 100% accurate. The DNA from the baby is tested against the DNA of the father. The father is responsible for ½ of the chromosomes in the baby's DNA and thus the test will exclude a father that does not have any matching pairs of chromosomes with the baby.

The inclusion paternity test is a bit different. The results of the inclusion paternity test will tell how likely the father is to be the biological match with the baby. In most cases, the results will appear as a percentage. The best percentage is 99% and above.

The results of the paternity test are determined by the number of loci pulled from the donors. The best test results come from a paternity test using 16 loci. The loci are another name for DNA match points. Some paternity testing facilities will only test 13 loci. These test results will be less accurate than a test using 16 loci.

While DNA paternity testing has advanced to great heights over the years with most test results reaching as high as 99.99%, the acceptable percentage for paternity testing is 97% probability.