A Turkish man decided to divorce his wife after DNA tests showed he was the father of only one of their twin boys, reported the mass-circulation Sabah newspaper on Friday.
Suspicious that his wife had been unfaithful the security guard from Istanbul identified only as A.K., had DNA tests performed on the three-year-olds.
The tests established with a 99.99-percent certainty that he was the father of only one of the boys, Sabah reported, adding that the result was confirmed by a forensic medicine institute upon the request of the court handling the ongoing divorce case.
The mother, identified as C.K., had maintained a relationship with a lover she had dated before her family forced her to marry A.K., the daily said.
The phenomenon of twins with different fathers -- known scientifically as heteropaternal superfecundation -- is very rare in humans, though more common in animals such as cats and dogs.
It becomes possible in rare circumstances when a woman produces two ova in one menstrual cycle, explained to AFP Professor Rusen Aytac, head of the gynaecology department at Ankara University's medical faculty.
"And if this woman has sexual intercourses with two different men at short intervals, this can result in a twin pregnancy, with each egg carrying a different genetic material," he said.
A.K. kept the boy he had fathered and disowned the other one, which ended up in a state care institution, Sabah said.
C.K., for her part, has received death threats both from her own and her husband's family and secured a court order preventing relatives from coming within 500 metres (yards) of her, it added.