The possibility of super-fecundation, when two eggs are fertilised during the same cycle by two fathers, is one-in-a-million, doctors in China say.
A mum-of-two's secret affair was exposed when a DNA test revealed her twins had DIFFERENT fathers, according to reports.
The woman, who has not been identified but is from Xiamen, China, had requested a paternity test with her partner last year so that they could formally put their twin boys on the city's household register.
But they were in for a shock when the test results reportedly showed that one of the boys did not belong to the dad.
According to reports in the Fujian Daily newspaper, the woman's partner had long wondered why his twins did not look alike, and why one of them had different eyes, mouth and nose - and did not resemble him in any way.