Man's unborn twin is his baby's father in incredible DNA phenomenon

In an incredible story, a man has failed a paternity test because his genes didn’t match his child’s, even though there were no other possible fathers.

The case, the first of its kind ever reported, was discovered to be the result of a ‘chimera’, where a baby absorbs the genes of an unborn sibling while in the womb.

After a series of paternity tests came back negative, the child’s parents, who live in Washington, USA, were understandably dumbfounded, so they decided to get in touch with geneticist Barry Starr of Stanford University to see if he could shed some light on the baffling situation. After he recommended they carry out a 23andMe genetic ancestry test, which looks at hundreds of thousands of markers in a bid to establish genetic genealogies, it came back that the father was actually the baby’s uncle. It was then Barry suspected it could be a chimera case.

Incredibly, it turned out the child's father had absorbed his unborn brother's genes, so his brother was technically the baby’s father. Only 10 percent of the man's cells are genetic matches to the boy and the rest belong to DNA from the man's unborn brother.

“Even geneticists are blown away by this,” Barry Starr, told BuzzFeed News.

This story has our heads spinning. Absolutely fascinating stuff.