The anonymous 19-year-old, 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.
How did she find out?
As per the report, the mother had doubts about the father of her kids and to confirm that she did the DNA test using the sample of the person she had thought was the father. After the test, she found that only one of her kids showed positive for the DNA test while the other one did not. “She then remembered that she had sex with a different man on the same day and when this second person took a test, it showed he was the second twin’s father,” says the report.
The explanation for this bizarre possibility lies in the biological phenomenon called heteropaternal superfecundation, in which the second ova released during the menstrual cycle is fertilised by sperm cells of another man in a different sexual intercourse. After fertilisation, the babies share the mother’s genetic material, but they grow in different placentas.
This phenomenon was initially presented by Archer in 1810. “Although rare in humans, heteropaternal superfecundation is common in dogs, cats and cows,” a report by The Guardian says.
Two scenarios can be explained in this: First, a woman can release two eggs at the same time. Since sperm can survive for a few days it would be possible to have sex with one father-to-be in advance of the egg being released, and another just after ovulation. In the second scenario, the woman releases two eggs a few days apart but in the same reproductive cycle.
As per the media report, only 20 other such cases have been reported so far.