A woman gave birth to twins with separate fathers after having sex with two different men on the same day. The mother, who has asked not to be named, lives with her two sons in the small town of Mineiros in the state of Goias, Portugal.
When the twins were eight months old, the man believed to be their father took a DNA test - however the results only came back as positive for one of the babies. The mum said: "I remembered that I had had sex with another man and called him to take the test, which was positive.
"I was surprised by the results. I didn't know this could happen and the babies are very similar." According to the Mirror, the twins' birth certificate still names just one man as the father of both children.
She added: "He takes care of both of them, helps me a lot and gives them all the necessary support that they need." Dr Tulio Jorge Franco has been studying the manner of the unusual pregnancy, which is understood to be only the 20th known case of heteroparental superfecundation to use its scientific term.
The doctor explained to Portuguese news outlet G1 that such a pregnancy happens when "two eggs from the same mother are fertilised by different men. The babies share the mother's genetic material, but they grow in different placentas".
He added: "The pregnancy was super smooth, without any complications. The boys were born healthy and have never had health problems.
"It's extremely rare. It happens once in a million. I never imagined that I would see such a case in my life."
The doctor made the decision to disclose the story this week with the twin babies now one year and four months old.
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