It has emerged that a woman is pregnant with two babies but doctors claim that they are not twins.
Julia Grovenburg's ultrasound report has revealed that she will have two kids with husband Todd, but physicians are of the opinion that they were conceived on two separate occasions.
According to statements from KFSM-TV in Ft. Smith-Fayetteville, Ark, doctors have hinted that baby girl Jillian was first conceived while baby boy Hudson was conceived two-and-a-half weeks later.
Such a rare case, when mother conceives another child while pregnant, is called superfetation in medical terminology.
"It does really sound like this is a true case of different conception times for these children," Fox News quoted Dr. Karen Boyle of the Greater Baltimore Medical Center, as telling ABC News.
"When the woman had her ultrasound initially, they saw one sack, one baby developing, and that baby had a certain gestational age; then they noticed a second heartbeat in a child that was much, much younger developmentally," the expert added.
However, to confirm a case of superfetation, doctors need to conduct chromosomal and metabolic tests on the babies after they are born.
Seemingly, superfetation is so rare that Boyle has heard of only 10 reported cases.
Meanwhile, Jillian and Hudson have been given different due dates.