A Washington State man failed a paternity test because of his unborn twin.
The 34-year-old and his wife had help from a fertility clinic to get pregnant. When they gave birth to a healthy boy medical records showed the baby didn't have the same blood type as either parent.
BuzzFeed reports that an at-home paternity test revealed the man wasn't his father. At first, the couple was pretty angry, thinking the fertility clinic used the wrong sperm -- but it turns out it they just made medical history.
Scientists determined this was the first-ever reported case of a paternity test being fooled by a human chimera, someone with extra genes absorbed from a twin lost in early pregnancy.
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 -- or the would-be father in this case.
So, the Washington father is genetically the baby's uncle and the real father is actually a ghost.