A 45-year-old woman gave birth on October 15, after reporting to the hospital for what she thought was kidney stone pain.
Beth Clay, of Marina Del Rey, California, and her husband Scott, 51, told KTLA that they had no idea she was pregnant.
In the past nine months, Beth says she kept up an active lifestyle and was on a strict diet that helped her lose 15 pounds.
When they welcomed little Liam Ryder Clay to the world earlier this month, they were baffled because Beth wasn't even showing her final months of pregnancy.
"I was like, 'That just can't be real.' It's all contrived, never could happen. You would know if there was a baby in your belly, but we're living proof," Scott said, adding that his wife never even felt the baby kick.
Beth, an artist, says her doctor has an idea of why she her belly didn't swell as much.
"The doctor feels sure that he was behind everything, behind my kidneys behind my liver," she said. "I was in tiptop shape, and then the next three days, here's this little rascal."
Scott says he feared that their baby might be still born, since his wife didn't feel the baby and didn't have any prenatal care.
Liam did spend a few days in the neonatal intensive care unit but is now as healthy as ever and at home with mom and dad.
The Clays already have two adult children, 20-year-old Will and 27-year-old Maggie. The couple have already seen one of their children - Maggie - married. 3
But they say they're excited to start all over again with baby number three.
"We waited a whole day before we told any of our family,' Beth said. 'Just so we could absorb what was actually happening, it's huge."