(PCM) We had always wondered if something like this was truly possible and it now appears that it is indeed possible for a set of twin to be born with two different fathers. A set of newly born twins in Vietnam are being labeled as bi-fraternal, meaning they have two different fathers. A series of DNA tests conducted on the twins have solidified this result.
While the twins develop normally side-by-side in the mother’s womb, the DNA test revealed that they actually came from two separate eggs that were individually fertilized by the sperm from two different men. Such an occurrence is incredibly rare and here in the U.S. there have only been two reported cases of bi-fraternal twins. It is not very often that eggs are fertilized during separate acts of sexual intercourse within the same ovulation period.
A woman’s egg has a life span of 12 to 48 hours, and a sperm for seven to 10 days, so there’s about a week’s time for potential overlap and a situation like this one to have the potential to occur. There are less than 10 cases in the world with twins that are known to have two different fathers, however there is the possibility that more exist where the parents and the twins either don’t know about it or do not want to reveal that information.