The strange case of twins with two different fathers

In a case that sounds more like the makings of a daytime TV talk show than a real-life court proceeding, a New Jersey judge ruled that twin girls were fathered by two different men.

The story began to unfold when a woman sought child support payments from a man she claimed was responsible for her pregnancy. According to a report in The New Jersey Law Journal, a DNA test was ordered by the Passaic County Board of Social Services, which found that the mother's eggs had been fertilized by sperm from two different men.

Passaic County Superior Court Judge Sohail Mohammed ruled that the man the woman claimed was the father, identified in court documents as A.S., will only have to pay child support for one of the infants.

The mother, identified only as T.M., gave birth in January 2013. She admitted in court testimony that in addition to A.S., she had sex with a second, unidentified man the same week her pregnancy began.

While the court deemed the case rare - Judge Mohammed wrote in his opinion that he found only two other court cases nationally on the matter - experts say it's very plausible and may even happen more often than we may think.

"Normally, when a woman ovulates, she's only producing one egg, but that's not always the case," Dr. Cynthia Austin, a fertility specialist at Cleveland Clinic Women's Health Institute, told CBS News. "Sometimes there are two." When two sperm fertilize two eggs, fraternal twins are formed. However, since sperm can remain alive for several days inside the body, it is possible that sperm from two different men could fertilize two eggs during the same menstrual cycle. As a woman is fertile for five to seven days a cycle, "the intercourse with different partners can happen days apart," Austin said.

DNA expert Dr. Karl-Hanz Wurzinger testified during the New Jersey case that T.M.'s twin daughters were fathered by two different men. He authored a 1997 study that estimated 1 in 13,000 paternity cases involved twins with separate fathers.

"Sometimes it's very obvious," Austin said, "if the father is one race and the babies are two different races." However, there may be instances where both the mother and father are unaware that such an incident has occurred. "I would say the vast majority of times, twins with different fathers, it goes unnoticed," she said.