HANOI, Vietnam, March 9 (UPI) -- A pair of fraternal twins born in Vietnam have been found to have different fathers according to local scientists.
The family decided to have the 2-year-olds tested when family members noted that one twin had thick wavy hair, while the other had thin straight hair.
DNA tests were performed on the two at the Center for Genetic Analysis and Technologies in Hanoi and Le Dinh Luong, president of the Genetic Association of Vietnam confirmed that they do in fact have two different fathers.
The rare situation is known as heteropaternal superfecundation and occurs when a woman's egg is fertilized by two partners in a short period of time.
Luong said the family was surprised by the result and told the BBC that the results were "100%" correct.
"There are only less than 10 known cases of twins with different fathers in the world. There might be other cases but the parents and/or the twins were not aware of it or didn't want to announce it," he said.
Further details were not revealed due to Luong's confidentiality agreement with the family.