A father in Vietnam began to grow suspicious of his children’s paternity when family members continued to point out that the twins looked completely different from each other. So, the father requested a DNA test.
He first thought that maybe one of his twins was switched at birth in the hospital. Now, at 2 years old, one sibling has thin, straight hair, while the other has thick, wavy hair. The identities of the children have remained anonymous to protect them.
The test confirmed his theory beyond his wildest imagination: One of the twins was his biological child, while the other belonged to a different man.
The rare occurrence is called bi-fraternal twins, an event where each sibling has a different dad. In this case, two separate eggs were fertilized by two different men.
This can happen when a woman has intercourse twice within the same ovulation period.
“Our Centre for Genetic Analysis and Technology lab has tested and found a pair of bi-paternal twins,” Dr. Le Dinh Loung said. “This is rare not only for Vietnam, but for the world.”
This is the first case of bi-fraternal twins in Vietnam, but there was already a previous case in New Jersey. Similarly, the father there didn’t suspect his wife had an affair until years after the twins were born and began to look different.