by Staff writer
It is biologically possible for twins to have two completely different fathers.
The phenomenon is called heteropaternal superfecundation and it occurs when two of a woman’s eggs are fertilized by sperm from two different men.
Ordinarily, a woman becomes pregnant because one of her eggs has been fertilized by sperm.
But in the case of heteropaternal superfecundation, a woman releases multiple eggs within a week apart.
Within that narrow time frame, two eggs can be fertilized by sperm from two different men she has sex with.
The product is a fraternal twins with two different fathers.
There have only been seven cases of twins with different fathers reported worldwide since 2011, according to the AP, including one case in the United States in 2015.
In the 2015 case, fertility specialist Cynthia Austin of the Cleveland Clinic Women’s Health Institute, told CBS News that twins with two different fathers might even occur more regularly, but go unnoticed.