Fraternal Twins
Nurses show a pair of fraternal twins to their mother (bottom) after they were born at the IVF centre of a hospital in Xi'an, Shaanxi province August 16, 2012. Reuters/Stringer

A fourth case of twins being born with different fathers was recorded in Vietnam. The second and third cases, which are rare medical events, happened in 2009 to a woman named Mia Washington and in 2013 to an unnamed woman in New Jersey. The first was in 1997.

The Vietnamese twins are already two years old, but the case was reported only recently, according to Agence France Presse. The twin underwent testing because of the very noticeable differences in their physical appearances, reports Tuoi Tre, a state-run Vietnamese daily.

Le Dinh Luong, Genetic Association of Vietnam president, confirms, “Our Centre for Genetic Analysis and Technology has tested and found a pair of bi-paternal twins.” He adds, “This is rare not only for Vietnam, but for the world,” quotes The Telegraph.

The relatives of one of the twin’s father suggested the DNA tests because of the completely different looks of the pair. Medical experts have confirmed previously that the case of fraternal twins having different fathers is possible if the woman had sex with two different men during the same ovulation period.

The first case involves Mia Washington who also submitted her twins, Jordan and Justin, to DNA tests after noticing their different facial features when they were 11 months old. One of the fathers of the twins is her current partner, James Harrison.

Washington admits to being very shocked to discover the truth about the paternity of her two sons. But Genny Thibodeaux, president of Clear Diagnostics, said in 2009 when it happened, “it is crazy. Most people don’t believe it can happen, but it can.”

In the New Jersey case, it was a pair of twin girls who were born in January 2013 in Passaic County. The county’s Board of Social Services, filed for child support from the boyfriend in October 2014 after the woman, unaware the twins have two dads, named him as the father.

A superior court judge asked Karl-Hanz Wurzinger, a DNA expert, to confirm if it is medically possible for twins to have two fathers. Wurzinger cited the first known case in 1997, involving the medical phenomenon heteropaternal superfecundation. With the expert testimony, the boyfriend needed to support only one of the twins at $28 (AUD$38) a week.