Twins with two different fathers

In an extremely rare case, a man found one of his twin sons was not his offspring.

Zhou Gang from Yiwu of Zhejiang province cheated on his wife and had a pair of twins with his mistress. But the man found the older one of the twins did not look like him, so he took the twins for a paternity test. The result of the test astonished the man because it showed the older one of the twins is not the man's son.

A fertility expert said that normally, a woman produces one egg during ovulation, but in rare occasions, two. That means if the woman who produces two eggs during that period has sex with different men, twins may be fathered by two different men. And the chance of such a case is one in a million, according to the expert.