DNA paternity testing provides life-changing answers about biological relationships. Whether you’re seeking clarity for personal reasons, family matters, or legal purposes, receiving your results can feel like a significant moment. Understanding those results—and the science behind them—is just as important as the testing itself.
This guide walks you through everything you need to know about your DNA paternity test, so you can feel confident interpreting your results.
What is a DNA Paternity Test?
A DNA paternity test compares the genetic profiles of a child and an alleged father to determine whether a biological parent-child relationship exists. Each person inherits half of their DNA from their mother and half from their father. By comparing specific areas of DNA, the test can confirm whether the alleged father has contributed to the child’s genetic makeup.
Paternity testing is extremely accurate. When results show a match, the probability of paternity typically exceeds 99.99999%. If the tested man is not the biological father, the result will show a 0% probability.
The Science Behind the Test
Paternity tests are based on the analysis of short tandem repeats (STRs)—repeating sequences of DNA found at known positions on your chromosomes called loci. Each person has two copies (alleles) of each STR marker: one inherited from their biological mother and one from their biological father.
During the test, the laboratory uses polymerase chain reaction (PCR) to analyze these markers and identify the alleles present at each locus.
In a true biological parent-child relationship, the child should have at least one allele at each locus that matches an allele from the alleged father.
Understanding Your Test Results
Probability of Paternity
The primary result you’ll receive is the “probability of paternity”—a statistical calculation expressed as a percentage. This indicates the likelihood that the tested man is the biological father of the child.
Positive Results (Paternity Inclusion)
If the report states the alleged father is not excluded and the probability of paternity is 99.9% or higher (at DNA Tests Direct, this is often 99.99999%+), this means there is extremely strong evidence that he is the biological father. The child’s DNA profile shows a consistent match with the alleged father’s DNA at all tested markers, meaning the child has inherited DNA from the alleged father as expected.
Negative Results (Paternity Exclusion)
If the report states the alleged father is excluded as the biological father and the probability of paternity is 0%, it means he cannot be the biological father. This conclusion is reached when there are multiple mismatches (typically three or more) in the genetic markers between the alleged father and the child. These mismatches indicate that the child could not have inherited their DNA from this particular man.
Combined Paternity Index (CPI)
Your report also includes a Combined Paternity Index (CPI). This statistical measure represents how many times more likely it is that the tested man is the biological father compared to a randomly selected man of the same ethnic background.
For example, a CPI of 100,000 means the tested man is 100,000 times more likely to be the biological father than a randomly selected unrelated man. A CPI of 100,000 results in a probability of paternity of 99.999%.
What if the Mother’s Sample is Included/Not Included?
Including the mother’s DNA sample can be beneficial as it allows the laboratory to definitively identify which half of the child’s DNA came from her. This can sometimes increase the Probability of Paternity in inclusion cases or help resolve rare or complex situations. However, conclusive results can still be obtained without the mother’s sample.
DNA Tests Direct can provide accurate results whether or not the mother participates in the testing process.
Frequently Asked Questions About Paternity Test Results
How accurate are paternity test results?
Modern DNA paternity tests are extremely accurate. A properly conducted test will provide results with greater than 99.9% accuracy for inclusions and 100% certainty for exclusions.
Can a paternity test be wrong?
When performed by an accredited laboratory like DNA Tests Direct, the possibility of an incorrect result is extremely rare. Our dual-process testing methodology ensures every sample is tested twice independently to eliminate the possibility of error.
What happens if there’s an inconclusive result?
In rare cases (less than 1%), a test may be inconclusive due to sample quality issues or other technical factors. If this occurs, DNA Tests Direct will request new samples at no additional cost to ensure you receive definitive results.
How long do paternity test results remain valid?
DNA test results are permanent and do not expire. Your genetic profile remains the same throughout your lifetime, so the conclusions reached in your paternity test report will remain valid indefinitely.
Next Steps After Receiving Your Results
Receiving paternity test results can be emotionally significant, regardless of the outcome. Here are some suggestions for next steps:
If you received a positive result:
- Consider legal implications regarding custody, child support, or inheritance
- Update relevant legal documents if necessary
- Take time to process emotions and adjust to the confirmation
If you received a negative result:
- Consider additional testing options if questions remain
- Seek emotional support if needed
- Consult with legal professionals about any implications
At DNA Tests Direct, we understand that behind every test is a personal story. Our customer support team is available to answer any questions about your results and to provide guidance on how to proceed.
For additional information or support regarding your DNA paternity test results, please contact our customer service team.
