In what can be said as one in a million cases, a 19-year-old from Brazil gave birth to twins who actually have two different biological fathers. The girl who hails from Minerios in Goias, Brazil, explained that she took a paternity test because she wanted to confirm who the father was, reported the Daily Mail.

It was reported that the rare phenomenon occurred because she indulged in sexual intercourse with two men on the same day. After nine months, she gave birth to twins. When their first birthday came she had begun to wonder about their father, she made the decision to have a paternity test to confirm her suspicions.

She collected the DNA of the man she believed to be the father. Just one child’s DNA matched to him though. “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.” she said in a conversation with her local media.

The woman’s physician, Dr Tulio Jorge Franco, also told the local news source, “It is possible to happen when two eggs from the same mother are fertilized by different men. The babies share the mother’s genetic material, but they grow in different placentas.” As per the media report, only 20 other such cases have been reported so far.