Get ready to have your mind blown. The case study which is about to be revealed to you will sound like nothing real or believable but this is life and anything can happen.

A man failed a paternity test because the biological father of his child was his unborn twin. Yes, it does sound totally crazy but it did happen for real and it is more common than we might think.

About 1 in 8 single childbirths are thought to have started as multiple pregnancies. Cells from these miscarried siblings are sometimes absorbed in the womb by a surviving twin but are only rarely discovered by surprises such as the paternity-test puzzle.

In June 2014, a couple from Washington had a son with the help of intrauterine insemination a clinical procedure to help conceive a child (IUI– is a fertility treatment that involves placing sperm inside a woman's uterus to facilitate fertilization). The baby boy was born completely healthy, but strikingly, the blood type of the baby and his parents did not match. Both parent had blood type A but the child had blood type AB.

At that point only one explanation was possible: the clinic might have mixed the samples and the man was not the father of the child. During the time the couple were going through the procedure, the clinic was only dealing with an African-American couple, and given the child’s appearance this did not make any sense. So, they moved on to the next step and did an at home-paternity test and the results showed the man was not the father of the child. 

They decided to perform a more accurate paternity test which consisted of the taking cells from the cheek of the father and match them against the child’s genes but this text was negative as well.

The couple then decided to get in touch with a geneticist at Stanford University, Barry Starr, who said that “Even geneticists are blown away by this.”

After, the couple performed a series of tests and examinations and they found that only 90% of his sperm matched with genes of his body cells and 10% actually belonged to his brother, who was never born. What happened is that the man absorbed his twin genes in his mother’s womb. He is a human chimera.

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 “To our knowledge, this is the first reported case in which paternity was initially excluded by standard DNA testing methods and later included as the result of the analysis of different tissues. This case of chimerism yielding a false exclusion is thought to be unusual,” the study concluded.



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