A Dallas woman said DNA results have proved that her 11-month-old twin boys have different fathers.
Mia Washington, 20, and her fiance James Harrison, 44, told the Today Show they went to a DNA lab after realizing the boys did not have the same facial features.
Paternity test results showed that the toddlers do not have the same father -- a rare occurrence called heteropaternal superfecundation.
Doctors explain that Washington's ovary released two eggs, and that one was fertilized by one man's sperm and the other by a different man's sperm.
Dr. Hilda Hutcherson, clinical professor of obstetrics and gynecology at Columbia University told the Today Show that sperm can remain alive and viable for up to five days in a woman's reproductive tract. Therefore, a woman can have sex with different men within those five days and the sperm "just kind of hangs out there waiting," Hutcherson said.
Washington admitted that she had an affair and said Harrison has forgiven her for the infidelity.
"I raised him [Justin] from a baby all the way to now. He knows me as his father, and I know him as my son," Harrison explained.
They will explain things to the twins when they are old enough to understand.
Some other news will come sooner. "They're gonna have a baby sister," Washington told the Today Show.