What is a DNA Paternity Test?

A DNA paternity test is a DNA test that’s performed to determine if a particular man is the biological father of a particular child.  Each of us receives half of our DNA (half of our genes) from our biological mother and the other half from our biological father.  In a DNA paternity test, we are asking the question,


Does the alleged father’s DNA contain the genes that the child inherited (or possibly inherited) from its biological father?

If the alleged father does not possess these genes, then he cannot be the biological father and the probability of paternity is zero.  If the alleged father does possess these genes, then he cannot be ruled out as the biological father and the probability of paternity, in most cases, will be more than 99.9%.


 There’s more to DNA paternity testing than meets the eye.

Why Testing the Mother in a DNA Paternity Test Improves Accuracy

For greatest accuracy in a DNA paternity test, we recommend testing the mother’s sample whenever possible. Doing this allows us to determine exactly which half of the child’s genes came from her (and therefore which half came from the father).  Testing the mother also provides confirmation that the correct child was tested, because the mother must match her child genetically.  In most cases conclusive results are also achieved when the mother is not tested.  However, such paternity tests present a greater likelihood that an alleged father’s genes may match the child due to random chance. Not testing the mother may also reduce the likelihood that an intentional (deceptive) substitution of a child in the test will be discovered (this can be particularly important in cases where the child is a newborn and/or when the alleged father has not seen the child before).


How DNA Samples are Collected

For most paternity tests, the samples used by the laboratory as the source of DNA are called buccal swabs.  These are epithelial cells collected by rubbing the inside of the cheek of the mouth with sterile cotton-type swabs.  Collection of buccal swab samples is non-invasive, completely painless, and can be performed as early as the day of birth.  Other types of samples—such as blood, semen, nail clippings, hair follicles, and prenatal samples—may also be used, but these are only recommended in special circumstances where cheek swabs cannot be obtained. 

The results of a paternity test will be exactly the same for tests performed using buccal swabs or blood (or other samples) because the DNA found in our cheek cells is the same as the DNA found in all of the other cells in our body.

What is a DNA Paternity Test Revealing About You?

Does a DNA paternity test reveal other relevant information about your genetic makeup or predisposition to medical illnesses?   Absolutely not.  The genetic tests that are performed in a DNA paternity test do not provide any information about a person that is medically relevant.  On the contrary, the DNA tests used for paternity evaluations are only screened for this purpose and otherwise consist of DNA sequences that have no known function.

LB Genetics offers several options for DNA paternity tests, including our legally-admissible DNA paternity.  The appropriate testing option for you will depend on your particular situation or needs.  For more information about DNA testing for paternity, please call us today at +1-714-648-0468.

 By: Dr. John Taddie