A judge in New Jersey has determined that a set of 2-year-old twin girls in New Jersey have different fathers.

The startling discovery was made after the twins' mother sought child support from the man she thought was the father of both girls.

Paternity test results showed that she was both right and wrong. The man only fathered one of the babies.

There have been only two other cases in the country of this happening; until recently, it was thought to be impossible. However, two eggs can be fertilized by different men if a woman has intercourse with two in the same week.

This makes the girls both twins and half-sisters.

The judge determined that the father owes $28 a week in back support for the daughter he did sire.