Paternity testing is often a straightforward process when the potential father is available and willing to provide a DNA sample. But what happens if the father is unavailable, unwilling to test or has passed away? The good news is that in many cases, it is still possible to investigate biological relationships using alternative DNA relationship testing methods. By analysing the DNA shared between a child and the potential father’s relatives, experienced laboratories, like NorthGene™, can provide valuable confirmation of a biological connection.
Is it possible to do a paternity test without the father?
Yes – while a standard paternity test compares the DNA of the child and potential father directly, there are alternative DNA relationship tests that can help determine biological relationships when the potential father is unavailable.
These tests analyse the shared DNA between the child and other close relatives of the potential father, helping to build evidence of a biological connection. However, the suitability of these tests can vary depending on which relatives are available for testing.
Legal considerations
In the UK, DNA testing is governed by the Human Tissue Act 2004. Under this legislation, it is a criminal offence to collect or analyse someone’s DNA without their knowledge or consent. This means that any person participating in a DNA test must fully understand and agree to the process.
For children under the age of 16, consent must be provided by an individual with parental responsibility.
With this in mind, it is essential that DNA relationship testing is carried out by a reputable, responsible laboratory. NorthGene™ is UKAS accredited, ensuring that all testing processes are performed in line with strict quality standards, regulatory requirements and ethical guidelines.
You can learn more about consent laws in paternity testing in our recent blog.
Alternative samples
If the potential father cannot be tested for any reason, such as he is deceased, absent, unwilling to participate, other relatives may be able to provide DNA samples instead.
Possible alternative tests include:
- Siblingship: confirms whether two individuals are biologically related as siblings. For example, a child may be tested against another child with confirmed paternity from the potential father to confirm or exclude a biological relationship. At NorthGene™, our siblingship testing services can help determine whether participants are likely to be full siblings, half siblings or unrelated.
- Grandparentage: compares the DNA of the child with the potential father’s parents. This can help determine if the child is biologically related to the paternal family line and is commonly used when the potential father is unavailable or deceased.
- Avuncular: analyses the relationship between a child and a potential aunt/uncle. Since siblings share a large proportion of DNA, testing the potential father’s full sibling can provide additional evidence when direct paternity testing is not possible.
How accurate are alternative relationship tests?
DNA testing with extended family members can provide accurate confirmation of biological relationships, although these tests are less conclusive than a paternity test involving both the child and potential father.
The likelihood of obtaining a conclusive result depends on several factors – to increase the chances of getting a conclusive result, we recommend:
- Including the mother where possible.
- Including more than one potential relative, such as both grandparents.
- Ensuring samples are taken correctly to help us obtain a full DNA profile for each participant.
In some cases, results may initially be inconclusive. This occurs more frequently in second-degree relationships than in paternity cases, as there is less genetic overlap to analyse. At NorthGene™, we offer extended marker testing and can provide further analysis to ensure the best possible chance of achieving a conclusive result.
Find out more about understanding your results.
Choosing the right test
Every family situation is different, which is why choosing the most appropriate testing option is so important. At NorthGene™, our experienced team provides professional, confidential guidance to help you understand the testing options available and identify which DNA relationship test may provide the most informative results for your situation.
If you would like to learn more about our DNA relationship testing services, contact our expert team today or explore our website for further information.




