The Short of It
A 34-year-old white man has learned he is a rare human chimera, which means he absorbed his twin early in the womb. Incredibly, it was the cells from the vanished twin that fathered his child and led to this first-of-its-kind discovery.
Parents (who prefer to remain unidentified to maintain their privacy) in Washington state conceived their first baby through IVF with the help of a fertility clinic. When they learned their new bundle of joy had a blood type that didn't match theirs, the couple assumed the clinic had mistakenly used the wrong sperm.
An at-home paternity test confirmed their disturbing suspicion that the man was not the baby's father. A second test administered by a lab returned the same, unsettling results. But when the man and his wife confronted the clinic, they were told just one white male donated sperm on that day, so there couldn't have been a mistake.
A geneticist named Barry Starr then recommended the man take a more advanced genetic ancestry test, which showed the man was actually the child's uncle! Since the genes in the man's saliva differ from his sperm's, Starr began to believe the man was a chimera, especially given his two-tone striped skin, an indication of the phenomenon.
"That was kind of a eureka moment," Starr told BuzzFeed News. He was able to determine 10 percent of the man's cells match his son's, while the rest belong to a twin brother that was never born.
It's believed that one in eight births start as a multiple pregnancy. Only 100 reports of human chimeras exist in medical literature, however. This is truly a unique situation that will likely never happen again in our lifetime.
"Even geneticists are blown away by this," Starr said.