At the Mayo Clinic, everybody is rooting for Abbigail and Isabelle Carlsen, conjoined twins who will soon be separated.

Surrounding the twins in their room are photos of the 55 doctors and nurses who are helping with their care, well wishes scrawled in magic marker and boxes filled with some 500 cards, sent by friends and strangers.

"I just think Abby and Belle touched a lot of people's hearts, and the support is great," their mother, Amy Carlsen, said last week as the duo peered at her with blue eyes, smiled and jabbed each other in the face. "It's needed."

Specialists are preparing for a May 12 surgery to separate the twins, who were born in November joined at the chest and abdomen. Surgeons will face a tricky procedure that could last 10 hours.

The girls share a liver and its vein system, parts of the pancreas and small intestine, a breastbone and the sac around their hearts. Separating some of those elements will be a challenge, doctors say, and the twin who has the most reconstructive work faces the highest risk of complications. Doctors haven't decided which twin that will be yet.

"We wouldn't be going ahead if we weren't confident that there was a good chance for a good outcome," said Dr. Christopher Moir, a pediatric surgeon who is leading the medical team that will perform the surgery. "But these little girls, unfortunately, have a very complex conjoined system."

The girls' parents — who left their jobs and lives behind in Fargo, N.D., on Feb. 24 — have become a well-oiled team in caring for the twins, color-coding their clothing and bottles, for instance, to make sure nobody mixes them up.

"The closer the surgery comes the more anxious we get, just to put it behind us," said their father, Jesse Carlsen. "Every visit from the doctors seems more and more positive."

Since the mid-1990s, there have been about 250 separations around the world in which one or both twins survived, according to the American Pediatric Surgical Association. The separation of twins joined at the abdomen has had one of the highest success rates.

One morning last week at Mayo Eugenia Litta Children's Hospital, Isabelle, wearing yellow with red stripes, and Abbigail, in pink with red stripes, slept on their sides facing each other, sometimes bumping one another with their legs and arms. After waking up, they smiled, touched each other's faces and grabbed their father's fingers.

The surgical team, meanwhile, has been poring over scans and charts for a month in preparation for the surgery. At some points during the procedure, as many as 30 people could be taking part.

The overall strength of the girls has been a relief for the parents, who long to return home and restart their lives. Amy Carlsen, 26, is a nurse in Fargo while Jesse Carlsen, 29, is a road and bridge inspector for the North Dakota Department of Transportation.

"I can't wait to go home and be a family," their mother said.