If you’re a follower of CSI(or a die-hard fan of it, like me!) you’d remember the episode, Bloodlines, about the rapist who couldn’t be identified because he had two sets of DNA and had the CSIs in a fix. Don’t like CSI? Well, then what about that episode in Grey’s Anatomy(another favorite of mine, except when they killed McDreamy *sob*) where an adolescent turned out to be a hermaphrodite—and a chimera because his tumor turned out to be the testis of a varnished twin? You must know that one. No? How about when in House, MD(C’mon, you HAVE to like this one!) the boy is thought to be part of an alien experiment(torture *shudder*) when really he was a chimera? They were all engaging stories and perhaps why all of these are a common feature in all our must-watch-TV-series bucket lists.

But imagine our shock when recently, a 34-year-old man was told,” Sorry sir, you’re not the father of your newborn child—your unborn twin brother is.”

This event occurred when a US couple(who’ve chosen to remain unnamed because of concerns for their privacy), blessed with a perfectly healthy son born in 2014 with the help of a paternity clinic, found out that their son had a different blood type than that of his parents(Shocking, right?). Naturally, the father of the baby(or not, in this case) took an at-home paternity test only to find out that his son’s DNA didn’t match his own. Upset at the possibility of being conned by the paternity clinic, even though the clinic had assured them that there was no mix-up of the sperm, they decided to lawyer up, and also approached Stanford University geneticist, Barry Starr who conducted a genetic ancestry test, which resulted in the man being the uncle” of the baby and not the “father”.

The man was a human chimera, people who possess more than one blood type, whose sperm was found to have 10 percent of a genetic match to the baby. Starr also discovered chimerism in the man’s skin, which was two-toned – light and dark strips. The father was further found to possess two different genes in his sperm and his saliva. It was concluded that he had somehow absorbed the genes of a twin that had died in the womb, thus being unborn, and passed the genes of his unborn twin to his son.

According to the Independent, “Approximately one in eight single childbirths are thought to start as multiple pregnancies and occasionally cells from the miscarried siblings are sometimes absorbed in the womb by a surviving twin,” making human chimerism a common phenomenon, it is extremely difficult to identify a human chimera(partly because the genes only feature in detectable amount very few organs), coming to light exclusively by accidents like this one. But as more and more people turn to fertility clinics and as DNA testing progresses with an advance in genetics, multiple births don’t seem to be something of a far-fetched concept anymore.

So, the next time you find yourself having an offspring that is not quite yours, don’t freak out. You’re just a cool chimera!


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