Julia Grovenburg Gets Pregnant While Pregnant : A Superfetation Case

Julia Grovenburg from Arkansas is pregnant with two babies, however they are not twins and were conceived more than two weeks apart.

The Grovenburg babies may be a rare case of superfetation, or conceiving while pregnant, doctors said.

"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," Dr. Karen Boyle of the Greater Baltimore Medical Center, told ABC News' "Good Morning America Health."

"It does really sound like this is a true case of different conception times for these children," Boyle continued, adding that she could only find "about 10 reported cases" of superfetation.

Grovenburg, 31, and her husband Todd tried for three years to have kids.

"We even refused to do in-vitro or fertility drugs because we didn't want multiples. I guess God is having the last laugh."

Grovenburg's first baby, a girl, they've named Jillian is due on December 24 while the second, a boy, Hudsonis due on January 10, but doctors have suggested that both be delivered at the same time in December to avoid complications.

The couple was interviewed about their experience on the "Today Show." Check out the video.