When thinking about genetics a fascinating topic is twins and how much DNA they actually share. As most people know there are two common types of twins, fraternal and identical. Identical twins are considered to be, as the name indicates, genetically identical and all their genetic markers are the same. Fraternal twins, however, only share the same amount of DNA as full siblings. How does this apply to DNA Testing and particularly paternity tests?
Imagine if a child has two alleged fathers, and in this situation the two alleged fathers are twins. Whether they are fraternal or identical will determine how we approach this in the lab and whether or not a conclusive result can be found at all.
Testing Alleged Fathers who are Fraternal Twins
If the alleged fathers are fraternal twins testing is conducted as if two alleged fathers are full siblings without being twins.The best case scenario in this test is to collect a DNA sample from both alleged fathers. This way we can compare both individuals’ DNA and accurately determine which of the twins is in fact the father of the child. If one twin is not available for paternity testing then we must perform extended analysis. This additional analysis will have an additional fee associated with it. This analysis is done to conclude whether the tested alleged father is in fact the father or is more likely to be an uncle to the child. If you find yourself in this situation I recommend contact our Client Support group to discuss the best testing for you.
Testing Alleged Fathers who are Identical Twins
If the two alleged fathers are identical twins there is currently no way to determine which of them is the father of the child.
Testing Children who are Twins
The other question that can come up with twins and DNA paternity testing is about children. If the children are twins, do we have to test both to confirm the paternity of each? That depends!
- If they are identical twins, then no. They will share exactly the same DNA because technically they can from the same fertilized egg. With identical twins there is only one possible father.
- Fraternal twins, however, come from two fertilized eggs. So, in this scenario it IS possible that each twin has a different father. While this is extremely unlikely, it is possible. In this case we recommend that both children be tested for paternity.
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Daibaby says
Can you use one DNA test for twins?
Identigene says
Hi, Daibaby. Yes, you can, as long as your are OK with not submitting the mother’s DNA as well. Testing two children with an alleged father, however, requires an additional lab fee. I suggest you call us directly to arrange your test, since there isn’t a place on the paperwork for an extra child’s info: 800-344-9583.
Chelsea says
I wanted to know can prenatal Dna testing using mothers blood could be determined if the twins are fraternal?
Identigene says
Hi, Chelsea. Whether twins with two amniotic sacs are fraternal or identical can only be determined via DNA analysis, and that analysis can only be performed after the babies are born.
Monai says
Can A DNA Test Be Done On Fraternal Twins && Without The Mother & On The Same Test Just Different Swabs⁉️
HomeDNA Identigene says
Hi, Monai. Yes, you can do that. However, since you’re asking to have two different paternity questions answered, (Is this man the biological father of twin A and is this man the biological father of twin B), you would need to pay two separate lab fees even though you’re using just one kit. It may be simpler to just call us directly to set up the test, and we’ll send you out all needed testing materials directly: 800-681-7162.
Mark says
Ok guys a woman I’m with just had twins not identical twins tho and they did a DNA test on them but they did it just like they were identical twins and they are not would them doing the DNA test like that make a difference on who the father is
HomeDNA Identigene says
Hi, Mark. Are you saying they tested both twins or just one? If both were tested, then each twin’s data was run. So if the twins have different fathers, it would show.