Closeup of a cute young couple smiling

Can my DNA Paternity Test be wrong because I’m a chimera?

Human chimeras are a popular topic for TV shows and crime scene dramas. This extremely rare and interesting genetic condition can lead to the question “Can my DNA Paternity Test be wrong because I’m a chimera?”

Named for the mythical monster with a lion’s head, a goat’s body and the tail of a snake, human chimeras have two or more genetically distinct types of cells in their bodies. This anomaly is thought to be caused by the absorption, or fusing, of twins before they are born. This would cause the chimera to carry two sets of DNA in their body. One set of their DNA and one that would have been their twin’s DNA. This second set of DNA can show up anywhere in the body. A second, distinct set of DNA may be present in the skin, blood, or even reproductive organs of the chimera. This was what happened in the case of Lynda Fairchild, profiled in the ABC documentary.

She’s her own Twin

chimera formation dnaFairchild underwent DNA maternity testing shortly after the birth of her child. Results showed a poor match, as if she was the baby’s grandmother. It was concluded that Fairchild may have been a chimera, her body the result of the fusion of two non identical embryos at the earliest stage of development. Different parts of her body could have come from different cell lines. Further testing indicated that cells taken from her reproductive organs, contained different DNA than those taken from her mouth for the DNA testing and were a match to her children.

Though cases like this are often given a lot of press, their occurrence is very rare. No one knows exactly how many cases of human chimera there are, but most studies cite only 30 reported cases in all of human history.

What does this mean for DNA paternity testing?

An inclusion, or “positive” DNA paternity test shows that an alleged father and the child share the same DNA. Therefore that man is considered to be the biological father. The father’s DNA was passed to the child, and the loci (markers) all match up. It’s virtually impossible (that is, very, very unlikely) that possessing two sets of DNA would make someone appear to be a father when they are not.  Matches at all locations indicate a positive paternity test result, even if the father is a chimera.

An exclusion (when a man is not the father of a child) could potentially be affected, by someone being a chimera. It is possible for a chimera to pass one set of DNA on to their child but show a second set of DNA with a cheek swab, as in the Linda Fairchild case.  Even so, the child and the father would still likely show a partial match, similar to that of a child and an uncle, since the second set of DNA would be that of the father’s unborn twin.

Disputed Maternity Leads to Identification of Tetragametic Chimerism – The New England Journal of Medicine

Genetic Mosaics

Post Comment

*

* Required Fields

  1. my boy friend is a chimera and the dna test shows he only shares 2 sets of dna how do I show the father is the father in a dna or how to explain to a judge about the dna of a chimera

    • Hi Caroel,
      Thank you for your patience. We have consulted with our lab director in order to provide you with an accurate response. Did you test with IDENTIGENE? If so, we recommend you call our client support so we can look into the case specifics and explain the situation better over the phone. It would be difficult to give a response to your question without having looked in to your case. If you did not test with IDENTIGENE, we recommend calling the testing center you tested with so they may look into the specifics as well, seeing as this is unique circumstance. You can reach us at 1-888-404-GENE, Monday-Friday 9AM-6PM ET with any more questions. Thank you for your comment!

  2. Omg….. im glad that I gound this page. I had a paternity test done through the courts and via identigene and both came back negative. My husband who was at the time my boyfriend, was the only one that I was sleeping with and dating. My aon look just like him, and although physical characteristics doesn’t matter, I know he’s his father. How do u explain this if there was no other sexual partners

    • Hi Jessica,
      Thank you for your question. We cannot speak on behalf of the court’s DNA test if it was not done by us. Have you checked if they are an accredited laboratory? If I may ask, were you present to witness the collection of the alleged father AND child? It is very important you are certain the samples we received are from the participants you wish to test. We understand mistakes can be made accidentally, but they can also be made intentionally during the collection process. We test and provide our customers with 100% accurate results, based on the samples we receive. With our at-home testing kit, we trust our customers to provide us with the samples written on the envelopes. We cannot verify if the sample labeled “John Doe” really came from John Doe.
      We do offer court-admissible testing through IDENTIGENE as well. We set up an appointment for you and your party to get collected by a disinterested third party in order to prevent the mistakes throughout the collection process. If you would like to learn more about our court-admissible option or have any more questions in general, please call our friendly client support at 1-888-404-GENE, Monday-Friday 9AM-8PM ET. Thank you for your comment!

  3. I was ordered to take a paternity test last year by someone I was with Jan 2013 and twins were born Sept 2013. I was one of two names listed as possible fathers. I know the other person listed. He wasn’t tested because mine came back 99% possible to be the father. The twin girls are fraternal. One looks exactly like me but the other doesn’t look like me or the mother. She looks exactly like the other possible father. Could it be possible that they are bipaternal twins and my test was wrong for one of them??

    • Hi C Birdwell,
      Great question! The best recommendation we have for fraternal twins is to have them both tested against the alleged father. Fraternal twins do have different DNA, unlike identical twins who have the exact same DNA. I understand you already tested one of the twins, we recommend to have the second twin tested against you or the other alleged father to clear any concerns. It is difficult to know solely based off physical traits of the child who the biological father is. DNA is the most accurate option in determining paternity of the child. I hope this information is helpful, if you have any more questions please call our friendly client support at 1-888-404-GENE, Monday-Friday 9AM-8PM ET. Thank you for your comment!

  4. Hi There,
    My brother is dating a girl who gave birth a year ago. She realised she was pregnant when they were in separation with my brother, the child is now 1 and people say she looks like my brother. We took all 3 (alleged father “my brother”, the mother and the child) of them for DNA testing, results excludes my brother from being a father of the child. The girl’s family does not believe that the tests results were correct because the child looks like my brother. What could have happened?

    • Hi Yolanda,

      Although physical traits can be similar, ultimately, DNA determines a relationship between two people. IDENTIGENE provides the most accurate testing available on the market today. We have worked extremely hard to put measures in place that prevent any mistakes from being made throughout the entire DNA testing process from beginning to end. This is why the accreditation we hold as a laboratory are so important. We trust our customers to provide us with the samples they would like tested, the samples we receive are what our 100% accurate results are based off. Was the mother’s family able to witness the DNA collection of the participants? If they are questioning the results, we recommend a legal DNA test. Legal DNA tests are witnessed, collected and sent in by a disinterested third party. Leaving out any opportunity for tampering or fraud with the paternity test.

      I hope this information helps. If you have any more questions or concerns, please feel free to call our friendly client support at 1-888-404-GENE, Monday-Friday 9AM-8PM ET so we may discuss your situation in detail. We are more than happy to assist you! Thank you for your comment!

  5. Hi there. 4 years ago, i have give birth to a beautiful baby boy. His”father” and i was so excited since it was our first born. Unfortunately, this excitment didn’t take long. The father suspected that he might not be the father and ordered a dna test. But it came out negative! I am still in shock and not to tell you the disappointment with both families! I’ve tried to do another test, Maternity test, just to make sure if the laboratory was trustworthy. My son and I share at least 70% of genes, that is why I suspect a microchimerism case in there. Now, I want to know whether we can do another test just to see if my son doesn’t carry another set of DNA? If it’s the case, this can be the answer that I am waiting for ages! Thx for your help

    • Hi Chelo,
      Thank you for your patience in our answering your question, as we do understand that the results can be a life changing event.
      Everybody’s DNA consists of receiving half from their biological mother and the other half from the biological father. Microchimerism would not change this fact, ONLY half the DNA would come from the mother even though you share at least 70% of genes. Humans actually share 99% of their DNA with all other humans, even when not related in a family. The remaining DNA is what will make every individual unique.

      You are welcome to test again with the same alleged father or provide samples of another possible alleged father. Have in mind that when a conclusive result, either a yes (not excluded) or a no (excluded) is reached, the test will have to be recollected and paid for once more. You may also ask yourself if you were able to witness the collection and sending off of the samples. If this is a concern, you may also consider a legal test. A legal test is witnessed, collected and sent off by a disinterested third party. If you continue to have any more questions, please feel free to contact our friendly client support at 1-888-404-GENE, Monday-Friday 9AM-8PM ET. Thank you for your comment!

  6. Male is being alledged as father in paternity complaint. Male denies ever having sexual contact with the mother of child. Mother of child has had sexual contact with the full biological brother of the alledged father. Alledged father requested court ordered DNA testing..alledged fathers brother will not agree to DNA testing & mother has not named brother as a potential father. Can the alledged father be deemed the father of child when he is not based on sharing DNA makers with brother? How frequently does this happen? Alledged father stated to DHS prosecutor his concerns & wishes for extended testing but the prosecutor states this issue wont matter & states alledged father must be 99.9% to be deemed the father & that no 2 brothers will match 99.9%…what should he do? He does not want any false positives & have to deal with contesting the results..he is 100% sure he can not be the father..the mother is promiscuious, has history of lying & has an infatuation with the alledged father.

    • Hi Laurie,

      I understand that there is a chance that two brothers and their father are alleged fathers of this child?
      This is actually a fairly common question! Most people are extremely concerned that results will be incorrect if the two or more alleged fathers in the case are related.

      In cases where two or more alleged fathers are related to each other, definitive results are still possible. Two people, even if they are full brothers, still have very unique DNA profiles. Half brothers would have even more separation since they only share one parent, and so on. It is extremely unlikely that two people who are siblings would match the same child at all the markers tested for paternity.

      For the most conclusive results, test all related alleged fathers. The biological mother should be included as well. Testing with the biological mother will aid in eliminating half the DNA that the child has, leaving DNA that would have to match with an alleged father’s. This will also help in avoiding an inconclusive result, which means not being able to give a concrete answer to the question of paternity.

      If both fathers cannot be tested, be sure you let our lab know that there is a second, related alleged father who is not being tested. The lab can often perform additional analysis for conclusive results.

      Have in mind, our lab fee includes testing for an alleged father, mother and child. With any additional participant wanting to be tested there is an additional $89 fee. It is also suggested that you call our facility so we may be aware of the situation to better help you. You can reach our friendly client support at 1-888-404-GENE, Monday – Friday 9AM-8PM ET. I hope this helped answer your question! Thank you for your comment!

  7. Hello, my ex just found out that he had the sickle cell trait (SCR)but our child does not have it and I don’t have it. We did a DNA test and it showed he was the father. He wants to do another DNA test because the fact that he has the SCT was not disclosed! Could the DNA test come out different because of this blood disorder?

    • Hi Beautifulmix,
      The outcome of a DNA test would not be affected by a participant being a sickle cell carrier and does not necessarily mean that a child of a sickle cell carrier would have inherited the same trait. With one parent caring the sickle cell trait, there is only a 50% chance of inheriting the same blood disorder.

      I hope this helped answer your question. If you have any more questions, please feel free to reach us at 1-888-404-GENE, Monday- Friday, 9 a.m.-8 p.m. ET.
      We would be happy to assist you, thank you for your comment!

  8. It seems chimerism is more common than first thought, as many people could have started out as twins in the embryo state and fused. What happens when two different men are the father of the two different embryos and they fuse, it seems that the chimera will have two sets of dna from two fathers. I have a family member that might fall into this category. Your thoughts?.

    • Hi Daniel,

      After speaking with our lab directors, there have been no human cases documented in literature regarding chimerism in this way. However, if this did happen, they would indeed have two sets of DNA. It would be no different than if two embryos fertilized by a single man fused, but the genetic composition would be that of half siblings (one mother and two fathers) instead of full siblings (one mother and one father). Although, as you stated, this would be exceedingly rare and could only be confirmed by testing multiple tissue types in the suspected chimera. We recommend talking with a genetic scientist who can test multiple types of tissue to determine if chimerism is present.

  9. I have had a DNA on my youngest son the alleged father is albino and they test came back with a 5% chance to be the father. Could it be that his albinoism is causing the readings to be off? I had another man tested and he was proven 99.9% not the biological father. So my question is does being albino mess the DNA readings up since there is extra genetic genes?

  10. My son was born with a cord which hadtwo veins and four arteries. One of the men i was seeinb when cocieved him was southeast asian with only brown eyes in his family. The other was caucasin with blue eyes containing brown specks. A dna test said that he is not the caucasin mans child, but he has eyes with alot of green and blue, and he is unusually tall, especially for the son of a small asian man. I have blueeyes,but it seems strange that the brown eyes wouldn’t be dominant. I have ofyen looked at my son and thoight it so odd that he looks like he could be b oth mens son
    Whem i heard of chimera and tnought about by sons double umbilical cord i started to wonder. I am not so concerned a bout paternaty but wo.nder if he has that rate condition and migjt need to.know as an adult?

    • Hello Patty,

      Thank you for your questions. Although looks may hint to the paternity of a child, the only accurate way of identifying the paternity of a child is through a DNA paternity test. Since your first test came back as an exclusion, we would recommend a second DNA test with the other plausible father. Another thing to be aware of is the possibility of participant fraud. Be sure that you witness the swabbing of each participant and that you mail the package yourself, this way you are sure that all participants are being honest and that the samples come from the participants you expected.

      In regard to chimeras, chimeras are very rare. However, if you are concerned, a medical geneticist can determine whether someone is a chimera through a series of genetic tests.

      Hopes this helps with your questions and concerns.

  11. Both man was tested in both said 99.9 but as well as 0.50% for both man for my child what do this means

    • Nita,
      We are unable to understand your question. Do you have a case # you can send us so that we can look at your results statement to better explain the findings? Thank you.

  12. My sons Father took an at-home Paternity Test, he called to get the results and he states that my child is not his. I remember the dates of when I conceived which was Dec. 26th, I had another partner around Jan.12th or somewhere around that time, I remember thinking it was the 2nd partner at first, until i went to the Doctor on feb.2nd or 12th, and they told me I was 2mnths which means I got pregnant in Dec, I wasnt with anybody else in Dec., that could be the possible father, and im 100% sure the test is wrong. What can cause incorrect results. The father is a Twin(Identical), and he smokes, can that affect anything. Im not sure how Paternity Tests works, but I know something went wrong.

  13. Hello,
    why do laboratory request for fingerprint in dna paternity testing

    • Hello Oladokun,
      At Identigene, we do not request a finger print for paternity testing. For legal testing, we require a photo I.D.

  14. does mouth odour affect dna test result

  15. My wife was only with two men at the time of my youngest daughter conception. The other man and I are on the different in many ways. I also have a older daughter under the same problem. Two different Mothers, three possible fathers. My middle child a boy is from my wife and me, looks, acts is a younger virsion of me. The girls act alike, sound alike, but I didn’t raise the older one. The older girl’s children look like my son and I. The place where I got the DNA test done stated I was wasting my money. Also my mother informed me that I was suppose to be a twin. The tests (2) for both girls came back neg. What would be the next step for us to do. This is hurting them, for they don’t know who they are.

    • Hello Michael,
      If paternity has not been confirmed and you and the child’s mother want to know their true biological father, I would recommend a test. The IDENTIGENE test can be bought at major drugstores. You cannot rely on similar appearance traits, you need to rely on DNA. You being a twin should not have any negative impact on a paternity test except if the woman carrying your child slept with your identical twin – which doesn’t seem to be indicated in your comment. Unfortunately, all you can do is test yourself, your alleged child/children and the biological mothers. If you get “excluded” results, the determination of paternity is then up to the biological mother to test every man she had sexual relations with during the estimated time of conception.

      Best of luck. Feel free to call IDENTIGENE with additional product questions. 888-404-GENE

  16. Hello,
    I hope I can get some type of answer on how to go forward. I have a three year old son and a year ago I tested his father three times two times outside of court and one court ordered. Each time he was negative. I did not sleep with anyyY around the time I got pregnant but him. The dna matches 7 out of the 13 markers but he’s been said not to be the father each time. He looks just like him the same and the same dimples and looks like his siblings that was tested and came back to be his kids.I have no idea what to do I have spent so much money already and have come up with no answers to this. If anybody knows of any special testing I could do please give me the information on who to contact I’m completely desperate.

    • Dear Nymommy,
      I’m sorry you have not found the exact answer you are looking for. We can help explain some of your DNA paternity testing questions. When results are received, and the conclusion is “Excluded”, the alleged father and child may still have some markers in common. This does not indicate a biological relationship, it means those specific markers are common among the population. You and I could test together and get some of the same markers, this does not mean we are related, only that we share common DNA. In order for the alleged father to be the biological father the alleged father and child must match at each location (there can be mutations, but we do account for those and there would only be maybe 1 or 2) DNA and similar appearance traits are separate.

      It sounds like you have exhausted your DNA paternity testing with the alleged father you mention above. If it were me, I would test anyone else that I had sexual relations with in a two month time period that correlates with my ultrasound due date. As you know, babies can deliver early or late so the best date to work with is the one your OB/GYN gave you after the first ultrasound.

  17. my rheumatologist did a dna test on me and genetic says I don’t match myself what does that mean she thought it was interesting but I did not understand what she ment can anyone help.

    • Dear Charlen,
      We would recommend you speak with your rheumatologist about your results. We specialize in paternity testing not genetic testing. Sorry, we couldn’t be of more help.

  18. I recently tested. My son father n the results came back he wasn’t the father n I know he was the only one iwas with can eating right b4 the swab test effect the results i heard it does

    • Dear Stuck,
      Eating something just before swabbing will not change your DNA. Food will not change or alter a DNA profile. We ask that you dont eat or drink anything before swabbing because we don’t want food particles getting on the swab. The only thing these particles can do is make it more difficult to extract DNA. Because a result was given, you can trust that DNA was collected and tested. Now, this brings me to another question. Did you see the alleged father swab his cheek and place the three swabs in the collection envelope? Did you collect your DNA as well as the child’s DNA and place in appropriate envelopes and mail together? These are important questions that need to be answered. If you used the Identigene test kit, we are more than happy to discuss your result statement as well as help with “next steps”. Our phone number is 888-404-GENE.

  19. About 9 to 10 years ago I had my son tested with an alleged dad and it came back negative. There was only one other person I slept with, God is my witness. My son has been tested twice with that alleged dad and it cameback neg. At the age of 19 this was very fustrating and devastating. I know deep in my heart I was not sleeping around like that. The thing that worried me was when I called the dna testing center I will never foget what the lady said to me. I asked why did almost no strains match with the first guy and all but about matched with the second guy? The lady asked was the picture of the second guy the correct person. I said ges. She said the dna looks like this person is related to the child. Help me what should I do? I left it alone at 19yrs old because I was young didnt know what to do. Now im asking God for answers my son has to have a dad. He will be 11 soon and he is asking me about his dad. I dont knos what to tell my son.

    • Hello Mojahzars,

      Let me start by saying a picture of a person does not, and should not influence DNA testing in any way. How people “look” can be deceiving. Only a DNA paternity test will tell you if the alleged father is the actual biological father of a child. At this point I would recommend a legal paternity test. This is where all participants have their DNA collected by a third party collector. This collector is a non interested third party. The collector verifies ID, and takes photos of the participants in most cases. The collector will then send the samples to the lab for testing. This establishes a chain of custody and ensures the samples submitted are from the actual participants. This will help put your mind at ease.

      I hope this answers your question, if you do have any other questions please let us know.

  20. Why do people keep insisting on how rare this is??? The number of people I have encountered online who are believed to be chimera are way more then a hand full, plus how does anyone know how rare it is when noone is being tested for this??? Linda fairchilds children were took from her before anyone would even test her….so rare?? Really??? How can u be soo sure??

  21. I am extremely confused with all this DNA stuff. I have had two of three possibliies tested. The third is dead! I was extremely surprised to find out that the second was not the father 0% chance his family was as well.She looks just like like him. A lot like the rest of the family as well. Not to mention that she has a lot of the same characterics and personalities and has not been arounf the family in 13 years. I am wondering if I should go ahead and ask for a blood test and just chalk up the cheek swab as a bad test. How accurate is it? Please dont judge (Matthew 7).

    Confused

    • Hello So Confused,

      I am so sorry, you are in a tough spot. The cheek swabs are 100% accurate as long as the samples given are from the correct people. DNA is the same no matter where it comes from, it can be blood or cheek cells, the DNA is the same. If the alleged father that is no longer available has full siblings, or his parents are available, you can test the child with them as well. When the alleged father is not available the next best option would be to test the child with both of his biological parents. This is known as a Grandparent DNA test. There are other relationship DNA tests also available. We would be more than happy to help you determine if there is another way to test a family member of the third possibility.

  22. I recently had a paternity test done on my son. I’m A+ and his alleged father is O+ my son is AB+. We had separated in that time I sleep with someone else who was B+. He was tested and DNA was not a match to my son. The now alleged father is the father of my other children who all have O+ blood. How is this possible?

  23. Im A+ my sons father is O+ but my son is AB+. We have three other children together they are all O+. Before my pregnancy we split up and I sleep with someone else. The other guy is B+ and was DNA tested and he was not his father. How is this possible?

    • With an alleged father being O and the child being AB with you A, this is most likely an exclusion. The alleged father with the B blood type is most likely not excluded, however, a DNA paternity test is the only way to know for sure. If the results show that alleged father with the B blood type is excluded and you are sure he is the only other option, I recommend doing a legally collected paternity test with both possible father’s. The legally collected DNA test will ensure that the DNA being tested does in fact belong to the right people and can not be switched at all. You want to test all possibilities.

  24. I’ve known for some time that Im a chimera, I dont really have questions about my eye color, palm and finger prints changing or how it all seems to be connected to my biological night and day clock, and all of that stuff, but Im fasinated with both medical and psycological impacts of having 2 DNA stuctures. So does anyone know about any research that is being done regarding chimeras?
    oh and for Alex, do your personality types switch over at a certain time of day? or is it random?

    • HI Sam,

      I am not personally aware of research that is being done on Chimera’s. They are so very rare, only a hand full have been determined since the beginning of time. I would recommend doing some research online to see what you can find. Sorry I cant be of more help.

  25. After all this 40 YEARS FINALLY I GOT THE UNSWER OF MY LIFE. IM A chimera. I was confuses, mom told me I haf twin but she had a miscarred, and he died or she. I meet my father when I was 11 years old, we look a like , he got 19 kids in total from different women, whe I turn 26 years old my father and I went to do my dna for the emigration, so I can get my papers because he is american And I was born in mexico , my surprice after I I got the results of my dna me and my dad dna came out negative I came on shok and I never understand even my mom and now I understand why after all this year now understan my 2 personalties I got on me boy and girl and now I need to find out where to do me a chimera dna to find out if I carry 2 dna I hope some one can help me aire2puros@hotmail.com

    • Hi Alex,

      I recommend contacting our excellent client support team. They would be more than happy to speak with the lab directors to assist with getting answers you have!. You can contact them at (888) 404-4363 Mon-Fri 9am-8pm EST

  26. My husband did but he can’t figure out what the test read and to ask if mother and father were related to each other raised an eyebrow with not understanding the test the mother of the child was with different men, and me being his wife I am the one to help him with his children so we do need to know fully what’s going on,he went through your company for the test but doesn’t have the pass word you were asking about when we were trying to figure things out on the site can he still be helped another way?

  27. on the D18S51 the relationship index reads 0.0029 the child in that column is an 18 the mother is 17,18 and the father reads a 16,19 there is no match there when I went to pick up the results for the paternity test it was explained that the father was the father they asked mother and father were we related instead my other question is if the mother had sex with a guy who was albino and the child come out to be albino how could I be the father when the test read that there was a single inconsistency identified in the test?

    • Hello Keme,

      I am not sure I fully understand your quesitons, however, I would strongly recommend calling the testing laboratory that completed the test and ask them to explain your results. If you did go through IDENTIGENE, we are always happy to speak to you about your test results and answer any and all quesitons.

  28. It’s amazing how so many people have unprotected sex with multiple men in a short time, as it isn’t just pregnancy they should be worried about.

  29. Amber,
    I like to discuss very intresting case with you , this happend to one of my close relative and there life is misrable right now and i really need your advice what should they do to comeout from this issue. They did IVF treatment to conceive baby and after baby born they did paternity test now the Father’s dna is not matching with Baby they repeat the test but the result is same they did use home paternity kit for testing ..do you think there are some chance of DNA mutation ?

    • Hi Jacob,

      If there were mutations anywhere in the profile, it would not be enough to exclude someone as the biological father. Mutations do happen, and when that does happen the lab has additional markers they can test in the place of the mutated marker. If the alleged father was excluded, that would indicate there are too many mismatches on the DNA profile for him to be the biological father. If he still questions it I would recommend having them complete a legal DNA test. That way the samples are collected by a collection facility, they send the samples to the lab for testing so there is no question as to the validity of the DNA samples.

      I hope this helps.

  30. I really need help my son is 10 years old and we took a dna test with his father and it said it was 0% Now he look just like him I keep hearing talk about he might be a chimera(my son) I was never with any one else For 2 years is there any other test we could do on my son or my son and his dad to prove to him that he is the father it is no way possible that he is not the father? Why do the test show some index match and others dont and the test exclude him cause of the onces that dont match? Please help if possible

    • Hi Rebecca,

      The chances that your son is a chimera is very slim. I would recommend having your son and the alleged father do a legal paternity test. That way the samples are collected by a third party, ID is verified, and photos are taken in most legal collections. This will verify the DNA samples that are being tested really are from the correct participants.

  31. Hello,

    I have a friend who slept with someone 5 years ago and now she has a son who is a little over 4 years old. He was conceived around the time they were sleeping together. Well, he had a Home DNA-Paternity test done 2 years ago and it came back that he was the childs father. But she has been threatening him the entire time to not tell because she has lead the other man to believe that the child is his. Now he has come out with it to the other man. So, this guy decided to have his own home paternity test done and it came back that he is the father. How could this have happened? Two tests, two different fathers? I told him he should go to a DNA facility to make sure. What do you think? Thanks.

    • Hi Jennifer,

      I would recommend that the alleged father’s (both if possible) go in and have a legal paternity test completed. That way all of the samples are collected by a third party collector, ID is verified, and photos are taken in most legal collections. The collector sends the samples to the lab for testing to verify they are not tampered with by the participants. That way the lab can verify who actually sent in the samples and can test them to verify which is the correct biological father.

  32. The father of my baby was just ordered to pay child support and then he asked for a DNA test. We go in 2 weeks to get it done. He is the only man i have been with in 4 years, can a test come back and say it’s not his when I know for sure it is?

    • If he is truly the biological father the paternity test will show that! With child support cases it’s always best to make sure its a legal collection so there can be no tampering of the samples by either party.

  33. Recently me and my son did DNA test for his immigrant visa and the test result said we do not match DNA. He did twice and both results do not match. I am really confuse now. If the result doesn’t match I can’t prove he is my son. What should I do? Is there any further and more detail test I can do to prove he is my son.

    • Michelle,

      With Immigration DNA tests the collection should have been done by a collector to verify the testing lab has the correct samples from the correct people. If the test was done and the samples show there is not a match, you may want to have a second test done to confirm if you are sure the child is yours.

  34. My question is, can a “chimera” or “mosaic” match the mother’s dna but not the father’s?

    • It is possible but not likely. These situations are very rare. In fact only a handful of reported chimera cases have ever existed. That is something that would need to be tested on the child to determine if that is what has happened.

  35. I’m unsure of alot of things at this point in my life, so to ANY one who can help this is my isssue… i was in a relationship for 4years with a man (never had protected sex)nor a child, we split i had met a guy an we had sex once an the condom broke, well in that time my ex an i were consitering getting back together, well a month later i found out i was pregnant she was born on dec 20th her due date was the 30th my ex an i were together on april 1, we got a dna test done but came back he is not the father, yes they look alike, ears, toes,eye color. but i know thats not the determination. but what im having a hard time with is when the lady swab she placed them in indavidal envelopes an sent it off, is that normal? the other guy will not take a test.does it matter how young my little girl was when they took the test? they have 8 out of 16 on the test, help? i really dont know what to do..

    • Hi Melissa,

      Placing DNA samples in individual envelopes is normal. We want to keep the alleged fathers DNA samples separate from the child’s DNA samples, and sometimes collectors will place each swab in their own envelopes. However, they are usually mailed together inside the mailing address if that is what you meant. It does not matter how old the child is, there is no waiting period. 8 out of 16 markers for an exclusion is normal. Because there are markers that are very common among the population you can have some matches, however, in order for your bf to be the biological father, he has to have all markers in common with the child. The child receives one number from mom and one from dad. I hope this helps. If you do have more questions please feel free to write again or call our client support team at 888-404-4363 and they would be more than happy to answer your questions as well.

  36. Hello,

    I had a swab paternity test and the result came back 99.99% probability; however, my son’s blood type is A, my blood type is O, and the father’s is B. I thought it was biologically impossible for my son to have a blood type of A with his father having Type B. Is it possible? Thanks for any response.

    • Hello Greta,

      DNA paternity tests are more accurate the blood typing test, and this is because people don’t generally know what their blood type really is for certain. I would be happy to review your case with you if you have any further questions.

  37. I recently did a DNA test with the man i believe to be the father of my child. 12 out of 16 markers match…the report says not the father.The two could pass for twins, baby pictures up to teenage look like the same person…is it possible the test is incorrect?

    • Hello Angie,

      Because there are common DNA among the population, there are times when some markers to match. That simply indicates they are fairly common. In order to be the biological father of the child the father and child must match at each location. If there is one mismatch that could mean a mutation. In that case we would test additional markers for verification. Because there are 4 mismatches that does indicate the alleged father is not the biological father.

  38. Hi, I am a 76 year old female who has had lots of problems during my life. I am not interested in paternity test but what is a Chimera?

    I have a colon that has not worked, very bad other digestive problems, and numerous fatty tomors removed as a teenager. I have also had a CTS and they discovered that I have a cyst on my liver that was there at birth, congential.

    I had a colonscopy last fall and they discovered that I have more than double the colon of an average person. That is why my colon has never worked as the doctor said because of the excess colon. It get into kinks, and nooks and crannies that cause the problems.

    I was born in 1934, legally blind with nystagmus. My grandfather was an albino and I have those characterists–very fair skin with no pigment (can’t tan) My eyes are not the same. The right one sees farther away and very small and that eye is 20/400 and my left eye sees very close up and is 20/200. I can read anything with my left eye if I can get it to my nose. I was also born epelepic and spastic.

    I attended regular school and have a college degree. I have worked all my life, retiring from local government in 2000 after 24 years. So I have worked hard to beat the odds.

    I also was married for 7 years but am divorced. I have 4 children who range in age from 44 to 50. I have one son who is fair and looks like me but he has good eyesight. I have a daughter and two other sons who are dark haired with olive skin.
    My daughter also has some other congential problems like me. She has congential cataracts and immune system diseases.

    I have always felt like I was my own twin. My Grandmother was a twin and my brother has a set of twins and one of his 4 sons has a set of twins. My son who looks like me has my only two grandsons. His oldest son, was part of a set of twins and his mother lost the other twin through miscarriage.

    All of these things I have researched and it is hard to find information as I think that people think that these things make one a freak. My mother always said my problems were a curse. I don’t know why, since her father, the albino came from Donegal Ireland before 1900.

    Everyone who knows us says my mother wore a girdle all of her pregnancy with me and folks didn’t even know she was expecting. I always joke and say, no wonder something is wrong with me. She was even ashamed for me to go out in public when I was expecting. I had a wonderful Dad who worked with me to overcome a lot of my disabilities. He wanted me to be able to make it in the real world.

    Any one got any ideas or information that they have found, or if you have some of these problems, I would like to thank you for a reply. At 76 I guess folks wonder why I would want to know, but I have worked hard to try and overcome these diabilities and lead a normal life, but I can say it has been really hard. I need to know if this has happened how will it treat my descendants.

    Thanks for any feedback.

    Nina

    • Hi Nina,

      Thanks for your comment and sharing your story. It was a fascinating read. I’ll point out again, that I’m NOT a doctor, at all. Just someone interested in DNA. :)

      In technical language: a chimera is an animal (or person) that has two or more different populations of genetically distinct cells that originated in different zygotes involved with sexual reproduction. Chimeras are formed from four parent cells (two fertilized eggs or early embryos fused together). Each population of cells keeps its own character and the resulting animal is a mixture of tissues. Chimeras are typically seen in non-human zoology, but also discovered to a rare extent in humans.
      This condition is either inherited, or it is acquired through the infusion of allogeneic hematopoietic cells during transplantation or transfusion.

      This is to say, a chimera is a person with two separate and distinct sets of DNA.

      Albinism is caused by one of several possible genetic defects. It effects the bodies ability to produce and distribute melanin, a substance that gives color to the skin, hair and eyes. It can cause vision problems, as well as bleeding disorders, lung, and bowel diseases.

      Because it is genetic, is can be passed down to your children. More information can be found here: http://www.nlm.nih.gov/medlineplus/ency/article/001479.htm

      It’s great that you are thinking about how this can affect your children and grandchildren. Genetic testing is recommended for people who have a family history of Albinism. A visit with a geneticist would be a good place to start.

  39. I have a 5 month old little boy. I was with this man for a while than one night i slept with his brother. This happened 2 weeks in a row. Right after that was when i found out i was pregnant. We did a paternity test throught the court with one of them and then we used the identigene for the other one. Both test came back that they were both not the father. I wasnt with anyone else and im not sure what to do at this point. ive read places that i should have them both tested at the same time and also do extensive testing. Does anyone have any advice or know what to do at this point?

    • Bella, You are correct. In cases like this, it’s best to do a court admissible test (with witnessed collection) on both men at the same time. It’s important that the lab have ALL the information available to them in order to provide the best calculations possible.

  40. I had a paternity test taking for court for the father, that lives in another state than me. They never showed a pic of him and i got the test back they said it was 0% chances he was the dad. I know for a fact he is the dad! so i am waiting for a pic of him that was taking at the time and they will reschedule another one to be taken. Is there anyway he can have someone else take the test that looks like him?

    • Hi Lisa,

      The purpose of a legal paternity test is that the collector does verify identification and take photos if necessary to verify who was actually tested. The collector also signs that they witnessed the collection. My advise would be to wait for the photo to be sent to you for confirmation of who was tested. If you are still not comfortable I would then recommend doing another legal DNA paternity test with another company to verify results.

  41. Hi,

    I am 38 years old. After many years of hearing that my father was not my father, I decided to do something about it. My mother refuse to talk about it. The alledged father is 68 years old. He said that it was a great possbility that I could be his child. He agreed to take an DNA test. The test came back “the alleged father cannot be excluded as the biological father and the probability of paternity is 99.99%. The test is confusing. I think this means that he is my father. Is there any chance or any way possible this test result could be wrong?

    I do share some features with the father that raise me.

  42. Hi, i am 24 years old and i gave birth to a child with down syndrome, i went to take a DNA test to determind who my child father is. They did a test by phenotypes and i was woundering if the test would be right. phenotypes look at the childs characteristic…. of course my child doesnt look like neither one of us… He has Downs… Where they supposed to give a test using genotypes? I think my child got his 3rd 21 chromosome from me. whould that make my test results inaccurate? or does Chimera have anthing to do with my case?

    • Hi Sharde,

      We call the results “phenoytypes”, not “genotypes”, because we are reporting the data we see from the elctropherogram as the phenotype. It is a fragment length of DNA, and represents the number of repeat units at that particular locus. Because we cannot see the underlying sequence, we cannot call it a “genotype”. Your results are accurate because no one is using their external physical characteristics to determine paternity. Most likely the data at the D21 locus (D21S11) was not reported in your case due to trisomy at that locus. It is standard protocol to drop a locus in which 3 alleles are seen in any one individual.

  43. Pingback: Where can I get a negative DNA paternity test done? | Ask Kate

  44. Thank you Amber :)

  45. how do u read the test

    • Hi Keisha,

      For Paternity tests: Following paternity testing accreditation guidelines, results are reported with one of three possible statements. For example, if we tested John Doe, alleged father, and James Doe (child), our paternity test results report might say one of the following:

      John Doe is excluded as the biological father of James Doe.

      This means that John Doe cannot be the father of James Doe because the analysis shows that they do not share a paternity relationship.

      John Doe is not excluded as the biological father of James Doe.

      This means that John Doe is highly likely to be the father of James Doe because the analysis shows that they share a paternity relationship.

      To see explainations on results for all tests, please go to: http://www.dnatesting.com/dna-testing/paternity-test-results.php

  46. Dear Kate,
    I recently had two Dna test’s done on my two alleged fathers and they both came back saying netheir are my biological father :( . The second man the one i was hoping could be my father I am just wondering if he could have the rare condition (chimera) clutching at straws. he already as a daughter and see was born with her stomach organs outside her body can chimera do this ???? …….and also on 1 test it says my allel 1 CSF1PO is 11 and on the other it says it’s 10.3 thank you :)

  47. Hi Alex,

    A CRI score of 58 does not mean that you are related to the child. Even two completely unrelated people could have that score.

    If you want to more know about how paternity is calculated, you can read about it here: http://www.dnatesting.com/dna-testing/paternity-test-results.php

    To answer your question, no. It’s not possible that you are a chimera. It really is an EXTREMELY rare condition. I can’t high-light this enough. It’s reported and talked about so much, because it IS so rare. And the cases of people who don’t know they are chimeras are even rarer, since this condition usually carries other health conditions and mutations which you would certainly know about.

  48. i took a dna test with my oldest son but it came back excluded but they test the first person and he was not it do think i was with somebody thats is family to him

    • Your paternity test can only tell you if the man you tested is the father or not. It cannot provide any information regarding who the father may be.

      You would need to do another test, with the other possible father(s).

  49. Thank you so much for your reply. We are having some other tests done bc it turns out there may have been a problem with the company that did the test for us. i just really would like to know for sure who her father is and i hope it’s not the one night stand bc he is in no way interested in having a daughter, even one as cute as my angel. thanks again for your help and if you could recommend a good company for us to use that would be great. God bless.

    • Brandi, IDENTIGENE is an accredited lab, and can perform either a pice of mind paternity test (collected in the privacy of your home) or a legal paternity test (collected by a third party with chain-of-custody.

      I’d encourage you to call on of our test consultants (1-888-988-4783) to talk about your particular situation.

  50. Kate,

    Yes, that’s what I believe it had said. I do have to get another copy of those papers, because they disappeared and I haven’t seen them for about 4 years. I’ll get back to you when I recieve those. The “scientific language” does confuse me a bit. I do know that there was a lot of excusions on the test.

  51. I just need a little help. I have a 14 month old daughter. I had a long time boyfriend, we broke up, i had a one night stand, then i started a relationship with another man within about a month. The last guy has already been excluded as her father so i did a dna test with my long time ex. it came back negative, but both of us agree that she looks just like him, and has nothing in common with the one night stand. is it possible that he could be a chimera? Could we just test his brother with my daughter to see if there is any relation?

    • @Brandi: Thanks for posting your question. I completely understand your dilemma – and that’s a tough situation – but it’s very unlikely that your “long time ex” is a chimera. Chimerism is extremely rare, with only a few documented cases in all of genetic history.

      Secondly, if the paternity test shows that your ex is not the father, testing his brother won’t change the result. Testing someone related to the alleged father is always LESS conclusive than testing the father directly. In fact, these reports usually have a disclaimer such as “these results do not supersede a direct paternity test involving the alleged father.” In other words, even if an “uncle test” showed the possibility of a relationship, the direct paternity test, with its negative result, would remove all doubt.

      Unfortunately, “looks” have nothing to do with it (see this article on phenotype vs. genotype). A child may “look like” a potential father (or mother) and still not be their biological child.

      If you’ve tested 2 of 3 possible alleged fathers, think that they were honest in their sample collection, and received negative results for both, then the only other possibility is the third alleged father. You’re best bet is to test the third father. Even though it was a “one night stand,” he still could be the father. If you’d like to talk with us about your situation in detail, please feel free to email us or give us a call.

  52. Danny, I am having the same EXACT problem. I had a test done on someone who I know for sure is the father and the test came out 99.99% inconclusive. My daughter is now 4 years old and I still haven’t been able to get another test done yet. Her father doesn’t believe that he is her father, but he was the only one I was with anywhere near conception and she looks a lot like him and his mother.

    • @mrs.joshjohnson: Are you certain the test was “99.99% inconclusive”? Usually an inconclusive result doesn’t show any percentage, since it’s inconclusive. If the test does show “99.99%” that would likely indicate that the alleged father was “not excluded” as the biological father. In other words, genetic science would consider him to be the biological father of the child because the calculations are 99.99% certain that he IS the biological father. Perhaps you can post the exact wording of the paternity test (omit names for privacy, of course) and we could help interpret. Or, you could call us and we’d be happy to review the test with you (even if it was done at another lab, we can sometimes help interpret the scientific language on the report).

  53. Hi Danny,

    An incorrect paternity test result, and an inconclusive paternity test are very different things. Very, very, rarely are paternity tests incorrect. An inconclusive result simply means that the lab was not able to make a determination either way. There are many potential causes for this.

    If you have an inconclusive result, I would have another test run. Since the first paternity test was done by the state, I think it was probably done with chain of custody. For the best comparison, I’d recommend you have another AABB accredited lab (like IDENTIGENE) perform a court admissible (or “Legal”) paternity test.

    If the second lab cannot provide you with a conclusive result, they should be able to tell you why your paternity test result was inconclusive.

  54. I had a paternity test done by the state that i know the results were incorrect. My son is 10 and trust me I wish there was someone else. The results showed to be inconclusive, how can i see if this is what caused the results to come out incorrectly.