Nanganak ng Kambal ang Babaeng ito Pero Magkaiba ang Ama! Paano ito nangyari? Alamin!

Twins are normal. We are all aware of the two kinds of twins: identical twins who look exactly alike, and fraternal twins that don't look alike.

But what do you call a phenomenon with twins having the same mother, yet different fathers?

We know that identical twins happen when a sperm cell entered an ovum which was about to undergo mitosis.

Meanwhile, fraternal twins are conceived when two ovums are ready and are fertilized by different sperms.

But having twins with different fathers, or bi-paternal twins isn't a scientific impossibility.

That's proven by a couple from Vietnam.

For privacy purposes, the name of the people involved will not be disclosed as part of the confidentiality clause with the Genetic Association of Vietnam who conducted a DNA test in Hanoi.

This is what happened:

For two years, a couple from Hoa Binh province in Vietnam was asked the same question after conceiving their twins:

Why does your twins look different?

Yes, they were born on the same day, with the same gender, with only a few hours apart.

At first, they thought that it was only a normal case of fraternal twins. But they can't be more wrong.

Growing up together, the twins started exhibiting more differences between each other. One hild has a thick, wavy hair, while the other has a thin straight hair. The former did not resemble the father at all-- which prompted the father's family to pressure him into getting a DNA test. The worst case scenario for them was a hospital mix up.

But the DNA results showed that the twins have one mother and different fathers. This was conducted by the president of the Genetic Association of Vietnam, Le Dinh Luong. The phenomenon is a very rare case-- a first in Vietnam, and one of only a few in the world.

Scientists explained that this phenomenon, heteropaternal superfecundation, is feasible if the woman had more than one sexual partners at the time of her ovulation and, coincidentally, released more than one egg. Since eggs can survive for 2 days while sperm cells can survive 7-10 days inside a woman's body, it really is likely to happen.

We can only speculate about the activities of the mother but the real situation was not disclosed for privacy reasons.

Watch the news unfold here: