What is paternity?

Paternity means the fatherhood and is established when an accurate accepted paternity test is able to demonstrate that an alleged father is the biological father.

Paternity is excluded when the same methods and standards demonstrate that an alleged father is not the biological father.

To check if a man is the biological father of a child

What are these tests?

Paternity tests are genetic tests to check if a man is the biological father of a child by making use of unique DNA sequences to construct a DNA profile of each. DNA can be obtained from blood cells, tissue cells and hair roots.  Blood, tissue and hair roots have identical DNA and it is immaterial which sample is used for DNA paternity testing.

How does DNA paternity testing work?

DNA analysis involves the direct examination of the genetic material that a child inherits from its biological parents.  DNA is an essential component of all cells throughout the human body and is identical in all cells.  DNA in the blood is therefore the same as that in the skin, lungs, muscle, bone and various other tissues.  Each person’s DNA complement is unequivocally established at conception and never changes throughout life.  Every person’s DNA is unique except for identical twins.  Since it is so specific, just like a fingerprint, DNA paternity is the most powerful tool for establishing biological paternity. 

During the paternity testing, the DNA profile of the child is first compared to that of the biological mother.  The mother contributes half of the DNA markers if the DNA profile of the child. DNA markers not contributed by the biological mother have to be contributed by the biological father.  If the putative father (alleged father) does not have the DNA markers to confirm the paternity, he is excluded.  If the tested putative father’s DNA can contribute all alternative NA markers the probability of paternity is statistically confirmed and reported by the laboratory.        


How accurate is DNA paternity testing?

A DNA paternity test is the most accurate form of paternity testing presently possible.  If the DNA patterns between the child and the alleged father do not match on two or more DNA marker pairs, then that alleged father excluded which means that it probability of biological paternity practically zero.  He cannot be the biological father of the child.  If the DNA pattern between the mother, child and the alleged father match on every DNA marker pair, then we are able to calculate a probability of paternity of 99,9% or greater.  This result indicates that he is “practically proven” to be the biological father of the child.

What is the procedure to get a paternity test performed?

To perform a paternity test at DNA level a blood sample is required from the mother, alleged father and child.  Children of any age can be tested.  Unlike the traditional blood tests where the child had to be six months of age, there is no age limit with DNA.  Paternity testing can be performed on unborn children. 

Prenatal paternity testing can be performed with amniotic or CVS fluids collected from the mother’s womb prior to birth or with fetal tissue.  Paternity testing can also be performed using post-mortem specimens.

What is the cost to do paternity testing?

For the latest prices please contact Unistel Medical Laboratories at: +27 21 938 9213/4 or info@unistelmedical.co.za.

Can paternity testing be done without a blood sample from the mother?

Yes, it is possible to perform paternity testing by comparing DNA profiles from only the child and an alleged father when the mother is not available. However, it is strongly recommended that the mother be included in the testing whenever possible.

Why the Mother’s Sample Matters in Paternity Testing?

Although the mother's sample is not required for paternity testing, it is always highly recommended if the sample is available.

The DNA of humans is almost identical for all individuals. There is a very small amount that differs from person to person and it is these differences that DNA scientists analyze to identify people. A child inherits half of his genetic make up his mother and the other half from his father. An examination of the mother's DNA enables the lab to know exactly what half of the DNA was contributed to the child by the mother. This means that the remaining half, (the "obligate paternal allele”) had to come from the father.

Complete information which includes mother and farther increases the certainty of paternity testing. This certainty may exceed 99.9999% vs 99.9% without the mother.

In the above example, the mother (circles are female, squares are male) had to contribute an 8 or 15 to each child. The number underneath each child is the obligate paternal allele, and must come from the father. The  9 allele in child 5 excludes paternity.

Many people think that when it comes to genes, what you get is what you get. In some cases, that is true. If you have the genes for brown eyes, you will have brown eyes. However, there are a number of genes that only express themselves in response to environmental factors. For example, a person may have a genetic predisposition to a certain disease, but it will only affect the person if it is triggered. Triggers vary widely– stress, obesity, deficiency in vitamins, or a combination of these and many other factors. Think of it as an on/off switch. Research in this area of genetics is not yet well understood, but research is rapidly expanding. In the meantime, exercise and eat your vegetables; it may be more important than you think.