It turns out siblings can drive you crazy even when they never actually exist. Case in point, the site IFL Science reports on a man who repeatedly failed paternity tests, despite knowing the child in question was conceived through intrauterine insemination using his sperm. Genetic testing revealed that the biological father was actually the man’s unborn twin brother. So the kid’s father is his uncle, who never existed. Just give it a second to sink in.The bizarre paternity results stem from a condition known as “chimerism” where, as researchers note, “embryonic cells from dizygotic twins fuse early in development, leading to the birth of a singleton with two cell lines containing different genomes.” Simply put, this kid’s father had the genetic material of both himself and his brother, despite the fact that his brother was never actually born, because he basically absorbed his fetal twin’s life force in the womb like Shang Tsung in Mortal Kombat. As a result, scientists found that only 90 percent of the man’s genome was his own, while 10 percent was a “minor genome” left over from the dad’s fetal victim.
Luckily, the paternity tests were only conducted for curiosity’s sake. The parents became suspicious after finding that the child’s AB blood type mismatched their A type. Though it’s probably even more lucky that the explanation stems from the father being a chimera and not a real, live brother, because that guy would have some real explaining to do.