#WorldstarDidYaKnow - A 19-year-old Brazilian woman reportedly gave birth to twins who have two different biological fathers after she had sex with two men on the same day. DNA testing confirmed that each twin was fathered by a different man.. an extremely rare phenomenon known as heteropaternal superfecundation. It occurs when two eggs released during the same menstrual cycle are fertilized by sperm from two different men. Only around 20 cases have reportedly been documented worldwide.