Paternity Test Reveals Child Fathered By Twin

A failed paternity test usually exposes instances of infidelity, but for one Washington state couple, it revealed the existence of the father’s long lost twin. The twin’s DNA, it turns out, had been absorbed into the body of his brother after he died early in the mother’s pregnancy. Thirty-four years later, still inside the surviving brother’s body, it was used to produce the couple’s child.



Last year, the couple, who has kept their identity secret for privacy reasons, was thrilled at the birth of their healthy baby boy. However, their joy soon turned to confusion when they learned their son’s blood type did not match either of their own. Because the child was conceived in-vitro, the couple immediately suspected that there was a sperm mix-up at the clinic and turned to Dr. Barry Starr, a geneticist at Stanford University, for answers. “You can imagine the parents were pretty upset,” Starr told Buzzfeed. “They thought the clinic had used the wrong sperm.”

A DNA test confirmed the couple’s suspicions — the man was not the child’s biological father. However, he was the child’s uncle. Although, the couple was confused by the results, Starr immediately realized that he was dealing with a rare genetic phenomenon known as a chimerism. While most individuals have two sets of DNA — one inherited from each parent — chimeras have extra DNA. In some cases, such as this, the extra set comes from a long lost twin that they absorbed while still in the womb. According to The Daily Beast, chimeras can also gain their extra DNA as the result of a blood transfusion, organ transplant, or between a mother and her fetus while it is still in-vitro. Now, the medical community has acknowledged the Washington couple’s story as the first case of a paternity test getting fooled by a human chimera.