Dad Learns That His Twin Brother -- Who Was Never Born -- Is His Son's Father

Would your husband freak out if he took a paternity test for his own child and the result came back negative? Probably. That's what happened to one couple -- but it wasn't because the mom cheated. Thanks to a genetic abnormality, the man's son is actually his nephew.


An unnamed 34-year-old and his wife used a fertility clinic to get pregnant and had a healthy baby boy in 2014. After finding out that the baby's blood type matched neither of his parents', they did an at-home paternity test and were horrified to find out that the baby didn't belong to Dad.

Since they had some help conceiving the baby, their first assumption was that the clinic mixed up the sperm. I can't even imagine what they must have been feeling at that point. Obviously they loved the little guy and, I'm sure, wouldn't want to give him back, but it would be devastating to discover that your biological child isn't actually yours.

They consulted with Barry Starr, a Stanford University geneticist, after the clinic assured them that there hadn't been a mix-up. The father and son took a more in-depth DNA test to check for ancestry and found out that he was actually his son's uncle ... by the twin brother he never knew he had. 

More from The StirTwins Have Different Fathers, Paternity Test Reveals

It turns out that the dad is a "human chimera," meaning he has more than one set of DNA. It happens when one twin miscarries in the womb in the early stages of pregnancy, and the other fetus absorbs some of the genes.

Scientists believe the condition might not be as rare as we once thought, since it usually goes unnoticed. But with advances in medical technology in both fertility treatments and genetic testing, it's popping up more than ever.

If you ever find yourself in a situation where you might be wondering how your child could have a blood genotype that could not possibly be formed from the parents' blood types ... someone in your family just might be a chimera.


Image via © ANDRZEJ WOJCICKI/Science Photo Library/Corbis

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