Although it may seem strange, it is possible for twins to have different fathers. When twins have different fathers, they are known as “bipaternal” fraternal twins.
Typically, a woman will ovulate a single egg at a time. However, there are occasions where a woman may ovulate two eggs within the same cycle. Fertilization of multiple eggs does not necessarily occur during one single act of intercourse. When both eggs are fertilized by the same male, even if the eggs are fertilized at different times, the resulting twins are considered fraternal. When each egg is fertilized by a separate male, bipaternal fraternal twins occur.