The parents travelled to the UK for the birth after learning that the expectant mother was carrying conjoined twins.
The UK is one of only a few locations with doctors experienced in dealing with the highly unusual births.
Joined at the abdomen
The sisters were joined at the lower abdomen but were capable of lying flat on their back.
At first glance they appeared as if they were one single trunk with a head and limbs at both ends.
Although their spines were fused, their legs were independently formed and criss-crossed each other.
Birth problems
At birth, Jodie was active and breathing voluntarily with a good heart and chest movement and moving all four limbs.
In Mary's case, there was a minimal response from the cardiopulmonary system before it failed.
The medical team soon realised that Mary's heart and lungs were so poorly developed that she was totally dependent on Jodie for oxygen and blood circulation.
In other words, she could not exist without Jodie.
While Jodie's system did collapse from blood poisoning shortly after birth, her heart and lungs were reported to be later fully functioning - giving the doctors hope that she could be saved. She was also said to have the same mental awareness as other newborn children.
However, Mary's mental state was unclear. During evidence given in the initial court hearings, doctors said that she was moving her limbs and had opened one of her eyes.
Because there appeared to be no distinguishing point where Jodie's body came to an end and Mary's body began, surgery effectively meant an operation on both of the babies.
One of the three law lords who heard the case, Lord Justice Ward, said: "The moment the knife goes in to that united body, it touches the body of unhappy, little Mary.
"It is in that second an assault."
Separation?
Doctors believed that Jodie could survive separation because her long-term problems were "functional" rather than life threatening.
The only threat posed to Jodie, said the doctors wishing to operate, was that Mary was sapping her strength.
Separation would lead to the immediate death of Mary.
The courts finally ruled in favour of the doctors who wished to operate and the separation took place on 7 November 2000. As expected, Mary died. The surgery means that Jodie still requires substantial surgery to reconstruct her lower abdomen, rectum and possibly her sexual organs.
While there were many doubts about Jodie's medium to long-term prospects, in the days following separation the baby rapidly improved, as predicted by the surgical team.
Unhappy precedent
In 1993, doctors in the US city of Philadelphia sought to separate conjoined twins Amy and Angela Lakeberg, knowing that one would die in the operation.
After much anguish, the parents agreed to the operation.
Amy died immediately but Angela only survived for ten months.