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Paternity research

How to do a paternity search?


Genetic research is a powerful and useful tool when you have doubts about a parentage link between two people.


This gives you the opportunity to use your DNA to prove a biological relationship and thus dispel a doubt about a family member, confirm your membership from a legal point of view or find unknown relatives.

Unfortunately when you want to do this type of genetic analysis, unlike a genealogy test which will only allow you to have relationship matches by percentage, you must compare the DNA of two or more individuals to have a reliable result on your parentage.

So the first thing to do in this situation is to know:


Who is available for the DNA test?

What is the family situation with this person?

Which DNA test to choose?

The search for a paternal relation can then be done with close members of the family of the presumed father and depending on the participants available, a choice of DNA test will be offered to you.

paternity search

Who can participate in a paternity search?

As indicated  previously,  to do a relationship DNA test, you must compare the DNA of several people to  define a paternal parentage link . For this, we propose in this guide to put you in the position of:  

- A man

- A woman

- A pregnant woman 

Depending on your basic profile, you will be able to do genetic analysis with: 

- The alleged Father 

- Your Brothers and Sisters

- Your Grandparents

- Your Aunt or Uncle

- A first cousin

However, there are conditions for each of the participants and it is often recommended to include your biological mother to improve the results of DNA tests.

What are the conditions for each participant?

Participation of siblings:


Genetic analysis can be done between brothers and sisters or with only brothers and conversely only between sisters.


Also, it is not mandatory that siblings share the same biological mother for a paternity search with a DNA test.

sibling test


To carry out a DNA test between a grandson or a granddaughter and their grandparents, it is important to respect the following condition: both grandparents must take part in the test.


It is possible that genetic laboratories offer to do the genetic test with only a grandparent, but we do not recommend this choice, because the lack of genetic information will not allow us to provide you with a reliable and precise DNA result.

In addition, it is normal to specify that both grandparents must be the biological parents of the father sought. 

grandparent DNA test

Test with the

aunt / uncle:

You must choose a participant between your aunt and your uncle.


Using DNA from both is not necessary to get quality genetic results and the lab may charge you for the test twice.


On the other hand, it is very important that the participant chooses either the complete brother or sister of the presumed father.


(They must share the same biological parents) 

Avuncular DNA Test


Genetic testing with a first cousin can only be done between male individuals.


The DNA comparison will be done on the basis of the male sex chromosome which is transmitted only from father to son on the entire paternal line.


The condition is that the cousin must be a male line descendant of your grandfather.


(Your uncle's son or any other male descendant exclusively)

DNA Test with a cousin

What DNA tests are available?

Paternity test

To carry out a paternity DNA test you must compare your genes to those of an alleged father.


This genetic analysis is the most reliable and the most direct in confirming the filiation link between the children, boys or girls, and the tested father.


The biological mother is not obligatory, but can also take part in the test.

Sibling test

In order to verify a common paternity between brothers and sisters you can choose the Sibling DNA test.


The genetic analysis will offer you a percentage of relationship, which can vary according to your genes, it is therefore more accurate to do this test with several participants (more than two) to improve the precision of the results.


As for this test, the addition of your biological mother is essential, but not mandatory.

Grandparent Parentage test

Gene analysis between grandchildren and grandparents can be done with this DNA test.


Since the laboratory does not have the genetic profile of the alleged father, it is important to be able to use the genetic profile of your biological mother if possible.


The test can only be considered reliable with the participation of both grandparents.

Avuncular test (Aunt & Uncle)

The genetic test for the relationship between a nephew and/or a niece can be done either with the aunt or with the uncle.


We recommend crossing genders to have more distant genes and therefore a more reliable result:


- Niece with Uncle

- Nephew with Aunt

The analysis is always in percentage of relation, so it is always recommended to include the genetic profile of your biological mother if possible.

Y chromosome DNA test


The Y chromosome test is as reliable as the paternity test.


It will give you either a positive or negative answer depending on the family situation.


This test can only be done with male individuals to determine if they belong to the same paternal line.

Participants can be: 

- Presumed father

- Uncles

- Grandfather

- Brothers

- Cousin

X chromosome DNA test


The X chromosome test is a test with very high accuracy just like the paternity test or the Y chromosome test, it  you will give either a positive or negative answer depending on the family situation and especially depending on the participants.


This test can only be done between sisters or with the paternal grandmother and her granddaughter.


Depending on the context, it is also important to include the biological mother to have results.

Prenatal Paternity test

For this genetic analysis, which is done during pregnancy when the mother is still pregnant, you are required to make the genetic comparison with the presumed father.


No other family member can replace the presumed father before the birth of the baby.


The mother must provide a blood sample and the father a saliva sample for the test. 

How to read the results of a DNA test? 

The results of a DNA test can vary depending on the type of test performed, but usually they include a comparison of the participants' genetic profiles.


The results are usually presented in the form of graphs, tables or percentages, indicating the probability of a genetic link between the participants.

DNA Test Result
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