In a rare and surprising event, a 19-year-old Brazilian woman gave birth to twins who belong to two different biological fathers.
The woman from Minerios in Goias, Brazil, said she conceived after having sex with two men on the same day. She decided to take a paternity test because she wanted to confirm who the father was, Daily Mail reported. She then collected DNA samples from the person whom she suspected to be the father of her children. However, after two tests, the results were positive for one of the twins.
She then recalled having sex with a different man the same day. When the second person took the test, it came out to be positive for the second baby.
How is it possible?
The biological phenomenon of giving birth to twins with two different biological fathers is called heteropaternal superfecundation.
This happens when a second ova released during the menstrual cycle is fertilised by sperm cells of a different man from separate sexual intercourse.
Speaking to Globo, the 19-year-old woman’s doctor Tulio Jorge Franco said: “The babies share the mother's genetic material, but they grow in different placentas.”
According to the doctor, the case is extremely rare and a one-in-a-million situation.
Although the phenomenon is rare among humans, heteropaternal superfecundation is common in dogs, cats and cows, The Guardian reported in 2018.
There are about 20 other cases in the world where such a phenomenon had occurred, Daily Mail said.
The children are now 16 months old, local media reported. However, the case was only discussed by Dr Franco this week. One of the fathers supports the mother in taking care of both the children.