Conjoined twins from Zimbabwe will undergo tests in Toronto to see whether they can survive a life-saving operation to separate them, Canadian doctors said on Tuesday.

The 4-month-old twins, Tinashe and Tinotenda, were born joined from above the waist to below the chest and have two connected livers.

“It’s a little bit hard to be sure, but I would doubt very much that they would live beyond a couple of years (without separating them),” said Dr. Jack Langer, chief of general surgery at The Hospital for Sick Children.

The twins, who were born in a rural area of Zimbabwe, arrived in Toronto on Dec. 2 accompanied by their 40-year-old mother and a nurse.

“I think she (the mother) felt that this was very unnatural,” said Dr. Rachel Spitzer, the Canadian physician who delivered the twins in Zimbabwe.

“I don’t think she understood what she was seeing, but she’s become an absolutely fabulous mother to the boys. She’s very understanding and is very hopeful, but ... also very realistic ... she understands that this is a complex process.”

Doctors said the twins were in stable condition, though malnourished.

Chances of long-term survival for the twins are slim without the surgery, Langer said.

Tinotenda, the smaller of the two, is already showing signs of becoming a “donor” twin, with more blood flowing into his brother Tinashe’s liver.

Conjoined twins occur roughly once in every 50,000 births and few are born alive or live long. For twins who undergo surgery, one or both often die after the operation and the rate of survival beyond age 2 is just 20 percent.