An American neurosurgeon believes the 10-year-old Indian twins joined at the skull can be successfully separated but would await making a final decision on whether surgery was possible until more tests had been conducted.
Dr Benjamin Carson, director of pediatric neurosurgery at Johns Hopkins Children's Center in Baltimore, reached his initial conclusion after reviewing the results of tests conducted on sisters Saba and Farah in the past month at New Delhi's Indraprastha Apollo Hospital, where the operation would be conducted.
Any surgery would need the consent of the girls' family in Bihar. The girls' father, Mohammad Shakeel, said he would make up his mind after consulting relatives.
More tests, including a computer simulation of the operation, also needed to be carried out, Carson told reporters on Tuesday.
"These types of operations are primarily complex. There is a lot of planning that goes into it," said Carson, who has taken part in four operations to separate conjoined twins.
The Indian twins share a blood drainage vessel in the brain -- a major concern for doctors, who say they may need to graft blood vessels from other parts of their bodies to give the girls individual drainage systems.
An added complication is that one of the girls, Farah, has two kidneys while the other, Saba, has none. Both girls have only single names.
Carson said he and the Indian doctors were consulting with other surgeons around the world.
"We will be able to use the collective expertise, knowledge and judgment of all of those people to perhaps refine the plan, to make sure that we optimize the chances for success and we minimize the risk that is going to be involved," Carson said.
"If everything goes the way we plan, I expect they will both be alive," Carson said.
The surgery would be financed by Abu Dhabi's Crown Prince Sheik Mohammed bin Zayed Al Nahyan, who offered to pay after he read about the twins in a newspaper.
Conjoined twins are exceedingly rare and most are stillborn. Of those born alive, some 60 percent die within hours or days after the birth. The total number of conjoined twins joined at the skull worldwide is believed to be between 10 and 20.