Bi-paternal Twins (Twins with different dads)
Yes, they were born on the same day. Yes, they are twins. Yes, they have the same mother, but they have different fathers. You heard that right, twins with different dads. Reports have been going on about a confirmed case of bi-paternal twins in Vietnam.
A Vietnamese couple lately brought their fraternal twins to the Center for Genetic Analysis and Technologies, in the Hanoi, to have DNA tests, after the 34-year old father’s extended family members started questioning why the children did not look alike and assumed that there might have been a hospital mix up.
VNS, Vietnam’s state-run news agency, reported the family is from northern Hoa Binh province and the children are 2 years old. The two-year-old twins are the same sex, and while one has thick wavy hair, the other has fine, straight hair.
According to Le Dinh Luong, president of the Genetic Association of Vietnam, the DNA testing at his Hanoi lab confirmed that there was no mix-up in the hospital and that though the twins have the same biological mother, they have different fathers. The rare occurrence is said to be the first case in Vietnam, and there have been only seven cases of bi-paternal twins reported worldwide since 2011.
There have been another case, which was reported in the United States last year, when a court ordered a man from New Jersey to pay child support for one girl in a set of twins, after genetic tests showed he was not the father of the other.
How is this possible?
Professor Michael Permezel, the President of the Royal Australian and New Zealand College of Obstetricians and Gynecologists, told news.com.au that while bi-paternal twins are rare, he has seen some cases in Australia.
Bi-paternal twins could happen when the mother has sex with two different men within one to seven days in an ovulation period, he adds.
According to Dr. Keith Eddleman, director of obstetrics at Mount Sinai Hospital in New York told CNN last year, a woman’s egg has a life span of 12 to 48 hours, and a sperm is viable for seven to 10 days, so there’s about a week’s time for potential overlap and the fertilization of two eggs by two sperm from separate acts of sexual intercourse.
Le Dinh Luong said the family were shocked by the news and are trying to work out the best way to deal with the situation. Further details have been released to media in order to protect the family’s privacy.