DNA paternity testing is the method in which DNA is obtained and evaluated to determine whether two people are biologically parent and child. A test determines whether a man is the biological father of a person; also maternity testing determines whether a woman is the biological mother of an individual.
DNA testing is currently the most used technology to determine parentage.
Paternity testing provides a number of advantages–the primary of which is to establish a medical history, to the heritage, legal, or social divisions.
There are two types of paternity testing: postnatal paternity testing, which occurs after the baby is born, or prenatal paternity testing, which is carried out while the mother is pregnant. Postnatal paternity testing can be performed by obtaining a blood sample or a buccal swab of the proposed father, in combination with umbilical cord blood at birth, or of a blood sample/buccal swab of the baby after the birth and prior to discharge from the hospital.
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With prenatal testing, there are two types available: Invasive and non-invasive. Invasive testing can be done in two ways, either through a CVS (chorionic villus sampling), which makes use of a needle , generally through the cervix in the first trimester of pregnancy to obtain the chorionic villi, or by amniocentesis, where a needle is inserted through the pregnant belly in the second/third trimester to obtain amniotic fluid, which contains fetal cells for analysis. This is done in conjunction with the obtaining of a blood or buccal specimen of the proposed father. There is a small risk of miscarriage associated with an invasive evaluation.
Non-invasive prenatal testing (SIP) involves the obtaining of the blood of the mother in combination with the obtaining of a blood or buccal specimen from the father. Fetal DNA can be detected in the mothers’ blood as early as 7 weeks of pregnancy. The amount of fetal DNA extracted by this method may vary, depending on the mother’s weight. There is no risk of miscarriage with this type of testing.
A paternity test is not currently 100% accurate. With a DNA percentage test, the result, which is deemed the “probability of parentage”, 0% if the alleged father of the baby is not biologically related. The result is typically 99.99% when the alleged father of the baby is biologically related to the child. Very rare persons in two separate sets of genes, also known as chimeras, in contrast to a single set, which can lead to a false-positive test.
There are a small number of companies in the US that the offer of prenatal paternity testing–Raven, DDC, Battery data, and Natera are among them. The cost ranges from $1400-$2000. Most insurers do not pay for the paternity test; a disadvantage is if there is a concern for a particular genetic disorder–in any case, its best to consult with your insurance company directly.
Dr. Kecia Gaither is a double board-certified physician in OB/GYN and maternal Fetal Medicine and obtained the degree of master in Public Health.