– When Jesse Carlsen asked his 11-year-old daughters to pose for a picture at the local humane society, where they had just donated toys for the cats and dogs, Abbigail and Isabelle knelt — an arm’s length apart — and posed with goofy faces.

“Abby, move closer,” the father instructed, “pretend like you like her a bit.”

The moment Wednesday was a playful reminder of just how far the Carlsen girls have come since they were born on Nov. 29, 2005, as close as close can be — conjoined at the chest and abdomen, with a shared liver and small intestine, and two hearts intertwined.

A decade ago, they were the miracle babies who gained national attention when doctors at the Mayo Clinic in Rochester, Minn., attempted a daring surgery to separate them. Today, they are healthy, bubbly fifth-graders in Mandan who love gymnastics and cats and sleepovers and woke up Christmas morning to find new televisions under the tree.

It’s a success story that has astonished their family and doctors, even now, and inspired medical advances.

“My heart leaps every time I hear about the Carlsen girls or see a picture of them doing so well,” said Dr. Christopher Moir, who led a team of 17 surgeons to separate the girls on May 12, 2006, “because I know they beat the odds.”

Conjoined twins occur in one of every 200,000 births, but more than 45 percent are stillborn when delivered, and another 35 percent survive only the first day, according to the University of Maryland Medical Center. At the time of the Carlsen separation, 60 percent of all such procedures ended in fatalities.

The girls’ parents, Jesse and Amy Carlsen, alternate between wonder and worry over their family, which moved from Fargo after the girls’ birth to a home on the windswept prairie above Mandan.

The wonder comes from the spunk of two girls born attached and facing each other. They’re alike enough in appearance that they attempted a mom-sanctioned April Fools’ joke last spring, when they switched clothes and went to school as each other. But even as conjoined infants, they were different. Abby was the sensitive snuggler and Belle was the hyper talker — and in some ways, those differences have held up.

At dinner Wednesday, Abby raced through puzzles on the restaurant place mat while Belle drew detailed flowers on the pictures of horses. Abby chose Jackie Kennedy for a school history demonstration, while Belle opted for Marie Curie. Neither liked the presidential candidates much, but one backed Trump while the other bet on Clinton.

And do they ever compete: The girls beg their dad to decide whose artistic creation is better. And they insist that their teacher tell them how they did relative to one another on assignments.

“They’re always asking: ‘How’d she do? How’d she do?’ ” their mother said.

The worry comes from what they endured. The surgery left gaps in their chest walls, and both girls needed Gore-Tex implants to cover the openings; Belle in particular needed extra protection for her heart and lungs.

The surgeons made some delicate decisions. They gave the twins’ shared bile duct and duodenum — the top end of the small intestine that breaks down food — to Belle, while the lower section went to Abby, who had been the healthier of the two babies when they were conjoined. They correctly surmised that the remaining intestine in each girl would take over the roles of the missing sections, but Abby needed a particularly harsh surgery to reconnect her digestive system.

So naturally, any stomachache or tumble causes nervousness in the Carlsen household. When the girls went sledding after a recent snowfall, Jesse winced when Abby crash-landed and clutched her chest.

“Little things scare me,” said Amy, a registered nurse at Sanford Health in Bismarck, “because you just don’t know.”

They are far from sheltered. On the uneven bars, Abby is one hip spin from fulfilling the prerequisites to compete in gymnastics. Belle needs to hold a handstand on the beam long enough to yell “one gymnastics” to do the same.

Belle needed surgery to add Gore-Tex protection over her chest three years ago, and might need another procedure if she outgrows that covering. Moir hopes advances in tissue regeneration will be far enough along by that time that doctors can grow a new sternum with her own stem cells and safely implant it.

“The technology is just about there, but it’s experimental,” he said.

Which do I cut?

Time hasn’t eroded the memory of the Carlsens’ first ultrasound in 2005; Amy remembers the technician’s face as she tried to understand the image on the screen.

“I just knew something was wrong,” she said.

Separation surgery was possible because the girls had their own hearts and lungs, but the fusion of their liver and intestine made it unlike two prior separations at Mayo.

“You had to create two out of one,” Moir said. “We were getting right down to the limits of what each girl had left for reconstruction.”

Still, planning left Moir optimistic on the day of the surgery that he had cut the odds of death from the 60 percent rate in medical literature to 10 percent.

One challenge was moving Belle’s heart into her chest. Several attempts caused dangerous drops in her blood pressure until doctors found a placement that worked.

The nightmare scenario came hours later, when the surgeons were severing the liver. Despite planning, the anatomy wasn’t what doctors expected, and they couldn’t distinguish a blood vessel that Belle needed intact from a bile duct that Abby needed cut.

It was like a James Bond movie in which the secret agent guessed which wire defused a bomb, Moir said. “When we got to that point in the operation it was like, ‘now, I understand. Now I know why these other twins died” 60 percent of the time.

As the operating room team of 30 stood silently, Moir chose one vessel to cut and exhaled when bile dripped out. He had picked the right one.

Mayo has gained from the experience. Preparation for the Carlsens made Moir’s team adept at the surgery, and it paid off months later when another set of twins needed emergency separation. Today Mayo is frequently consulted on whether twins can be separated, but has completed only three such surgeries since the Carlsens.

Perhaps the biggest change that followed the Carlsen surgery was the broad use of 3-D printing of internal anatomy. Mayo doctors are exploring 3-D printing of actual implants, but Moir said that was inspired by a 3-D model of the Carlsens’ organs that was used for planning and practice. He keeps that model in his office.

“It’s a revolution in medicine and we started that 11 years ago with the Carlsens,” he said.

The girls tire of the separation story — “eh, that’s not us,” Belle said — but they remain curious. A picture of them as conjoined infants has a cracked frame from when one girl lifted it off the wall and dropped it to her sister.

Media attention has waned, but Amy wonders whether the girls will become doctors or journalists because they have been around so many of both.

For years, one of the last tangible reminders of their attachment was when they would be walking and — without realizing it — hold hands. That doesn’t happen much anymore, and the squirrelly girls don’t like to admit it, but Jesse said he still sees it once in a while.

“It’s infrequent,” he said, “but it’s crazy when they do it.”