Q: What if the alleged fathers are related? Can I do a DNA Paternity test with just one of them? Should I notify the DNA Testing lab?
A: You want to test all alleged fathers when doing any DNA paternity testing. This may be complicated at times; yet, for best DNA paternity results you want to test all of the alleged fathers, especially if they are related. If this is not possible, be sure to inform the laboratory conducting the paternity testing if the alleged fathers are related in any way.
Why this is Important
The DNA paternity testing laboratory needs to know how the alleged fathers are related, most especially if they are brothers. This is essential knowledge because the DNA testing laboratory can then also calculate the probability of an avuncular (Uncle) relationship. Brothers do have different DNA (with identical twins being the exception); however, if the biological mother does not participate in the DNA test by supplying samples, testing only one brother may yield inconclusive results.
Always include the biological Mother for DNA testing whenever possible for any type of DNA testing but most especially when the potential fathers are brothers.
If the alleged fathers are more distant relatives (such as first cousins) the DNA they have in common will not cause inconsistency on a DNA paternity test. However it is still important to notify the laboratory of the relationship.
Vanessa says
Hello,
my husband has two children outside of our marriage. He is willing to do a patenity test on the two children but the mother of the children refuse to comply. Can a paternity be taken if the mothre’s dna is not present.
Amber says
Hi Vanessa,
If your husband has the legal right to sign for the children to be tested, you can test him with the children. You must be aware there is a possibility that Paternity DNA results may come back inconclusive without the biological Mother. If that does happen we would contact you before releasing results to try and get the Mother’s DNA at that point. You can read more about why testing the Mother is important here: http://dnatesting.com/dna-test-questions/why-test-the-mother.php