This "one-in-a-million" pair of twins were born nine months after the 19-year-old had intercourse on the same day with two separate men. A mother from Brazil was having doubts about the identity of the twins' biological father. Due to this, she took a paternity test, but the results were far from what she expected.
According to a report from the New York Post, both of the men she conceived with came back as a match.
“I remembered that I had had sex with another man and called him to take the test, which was positive,” the new mother, who asked to remain anonymous, told local news outlets. “I was surprised by the results. I didn’t know this could happen, and the babies are very similar.”
The mother remained anonymous due to wanting to keep her privacy about the case and also due to the interest of the public in this extremely rare case. Doctors refer to this rare phenomenon as
Heteropaternal superfecundation is a very rare case where the twin babies share the mother's genetic material but grow in different placentas. Therefore, each baby inherited the genes of a specific biological father.
Dr. Tulio Jorge Franco, who is the mother's attending physician says that it is possible, but extremely rare for two eggs from the same mother to be fertilized by two different men.
The twins' mother told Globo that just one of the fathers is presently responsible for raising the 16-month-old children. It's unknown what function the other may have in their life. Dr. Franco referred to the incident as "one in a million" and stated that he thought there were only 20 other occurrences of the same thing worldwide. However, according to some medical professionals, there are currently about 400 instances recorded since modern medicine.
Heteropaternal superfecundation is actually quite common in animals like cows, dogs, and cats.