Paternity testing
- infotest ADN
- Dec 28, 2025
- 4 min read
Updated: 1 day ago
Paternity testing: which DNA test should you choose to establish biological kinship?
Do you have doubts about a biological link between a child and a presumed father? A paternity test relies on comparative genetic analysis to confirm or exclude paternity.
This type of procedure can be useful to:
resolve doubt within the family,
confirm filiation in an administrative or legal context,
find biological relatives.
Unlike genealogy tests (which provide matches and ancestry percentages), a paternity test requires comparing the DNA of two or more people to obtain a reliable result.
Before ordering, ask yourself three essential questions:
Who is available for the DNA test?
What is the exact family relationship between the participants?
Which DNA test is most suitable for the situation?
In this guide, you'll find the possible configurations, the conditions to respect according to the participants, and the available DNA tests.
Who can participate in a paternity test?
To establish paternal filiation, the DNA of several people must be compared. Depending on your situation, you may find yourself in one of these profiles:
a man,
a woman,
a pregnant woman (case of prenatal testing).
Depending on the available participants, the analysis can be carried out with:
the presumed father,
your siblings,
your grandparents,
an aunt or uncle,
a first cousin.
Important: in several configurations (siblingship, grandparentage, avuncular, X-chromosome), it is often recommended to add the biological mother if she is available. This can improve interpretation and accuracy.
What are the conditions according to the participant?
DNA test with siblings
Genetic analysis can be performed:
between brother and sister,
between brothers,
between sisters.
For a paternity test, it is not mandatory that the siblings share the same biological mother.
DNA test with grandparents
To perform a DNA test between a grandchild and their grandparents, there is one essential rule: Both grandparents must participate in the test.
Even though some laboratories accept a test with only one grandparent, this configuration provides less genetic information. The result will therefore generally be less reliable.
Another important point: both grandparents must be the biological parents of the sought-after father.
DNA test with an aunt or uncle
You must choose a single participant: your aunt or your uncle.
Testing both is not necessary to obtain a good result and may make you pay for the analysis twice.
Essential condition: the participant must be a full sibling of the presumed father, meaning they share the same biological parents.
Analysis with a first cousin (paternal line)
A genetic test with a first cousin can be performed only between males when the comparison relies on the Y-chromosome, passed from father to son.
Condition: the cousin must be a descendant of the male line of your grandfather (for example, your uncle's son, or another exclusively male descendant).
Which DNA tests are available for a paternity test?
The laboratory will choose (or offer you) the most suitable test according to the available participants.
The paternity test (direct test)
The paternity DNA test consists of comparing your DNA with that of a presumed father.
This is the most direct and reliable analysis to confirm a filiation link between a child (girl or boy) and the tested father.
The biological mother is not mandatory, but she may participate.
To verify common paternity between siblings, the siblingship test can be an option.
Results are often expressed as a percentage. It may therefore be useful to add more than two participants to improve accuracy.
Adding the biological mother is often recommended, without being mandatory.
This test allows the DNA of grandchildren to be compared with that of grandparents.
As the laboratory does not have the profile of the presumed father, adding the biological mother (if possible) can improve the analysis.
Key condition: the test is only considered reliable if both grandparents participate.
The avuncular test (aunt/uncle)
This test allows an evaluation of a relationship between a nephew or niece and an aunt or uncle.
To strengthen reliability, it can be interesting to cross genders:
niece with uncle,
nephew with aunt.
Results are expressed as a percentage. Here too, adding the biological mother is often advised.
The Y-chromosome test can be as reliable as a paternity test in certain configurations.
It provides a positive or negative answer depending on the family situation.
Important limitation: this test can only be performed between males, to determine whether they belong to the same paternal line.
Possible participants:
presumed father,
uncles,
grandfather,
brothers,
first cousin.
The X-chromosome test can offer high accuracy, comparable to the paternity test or Y-chromosome test, depending on the participants.
It can be performed:
between sisters,
or between the paternal grandmother and her granddaughter.
Depending on the context, adding the biological mother can help obtain more solid results.
This test is performed during pregnancy.
In this case, it is essential to compare the baby's DNA (via the maternal sample) with that of the presumed father.
No other family member can substitute for the presumed father before birth.
Required samples:
the mother provides a blood sample,
the father provides a saliva sample.