A woman in the US has given birth to twin sons each of whom have a different dad.
Texan Mia Washington was said to be shocked to find out that despite being born within seven minutes of each other, her sons are in fact half brothers.
Her partner demanded a DNA test after questioning why the two youngsters looked so different.
Research shows that there is around a one in 12 chance that non identical twins will have different fathers.
The phenomenon occurs when a woman releases more than one egg during her monthly cycle and has sex with different men during the 5 days around ovulation.
“Because sperm cells take a while to travel and eggs take a while to travel there can be an overlap,” said Dr Chris Dreiling, from the Paediatric Association of Dallas.
He added that the rare event was likely to be “the only time that we will ever see this occur in the city of Dallas”.
Mia’s partner James Harrison has agreed to stand by her despite her infidelity and help to raise little Justin and Jordan.