THERE have been at least two cases here where parents attempted to save their dying child by having another baby.

For little Ryan Foo, who had leukaemia, a precious transfusion of stem cells taken from his sister's umbilical cord when she was born proved a life line.

Now, 1 1/2 years later, Ryan enjoys a relatively normal life like any healthy five-year-old, and is believed to be the first child here with leukaemia saved by such a transplant.

Up to 20 per cent of such patients do not make it.

Another four-year-old boy who received stem cells from his baby sister a month earlier died of an infection.

Dr Tan Ah Moy of KK Women's and Children's Hospital (KKH), who handled both transplants, said that since Ryan received his gift of stem cells from baby sister Rachel, they have developed into healthy blood cells.

These cells have re-populated those in his bone marrow after chemotherapy and radiotherapy treatments - to destroy the cancer cells - also killed his immune cells.

Overseas, some have taken this process a step further, with the creation of so-called designer babies, where parents select in-vitro fertilisation embryos that would provide the best genetic match to help a sick brother or sister.

The number of children dying of cancer has been decreasing steadily over the years, and about eight in 10 are cured, said Dr Tan.

But with five young patients dying of cancer last year, the disease overtook accidents as the top child killer here, for those aged five to 14 years. Leukaemia is the major child cancer, with about two in 10 victims requiring stem-cell transplants.

Both cord blood and bone marrow are rich sources of 'unprogrammed' cells that can become all sorts of blood cells. For the 20 or so children a year here who develop severe blood disorders such as leukaemia or thalassaemia, a transplant is the only solution.

A patient who cannot find a match among family members must hope for one from an unrelated donor.

But this is unlikely because most established public cord blood banks are in the West, where donors are mainly Caucasian. Slight genetic variations make the chances of a match highly unlikely.

Because they were done earlier, bone marrow transplants outnumber cord blood transplants about seven to one at the hospital, said Dr Tan, the head and senior consultant of KKH's paediatric haematology and oncology services.

She is confident this will change. Cord blood cells, with their relatively immature immune cells, are less likely to attack the transplant patient's own body. This also makes it easier to find a match for cord blood since, unlike bone marrow, it doesn't have to be 100 per cent compatible.

Dr Tan believes the best chance at life for many patients will be the Singapore Cord Blood Bank, which is opening soon. Said its executive director, Dr Fidah Alsagoff: 'This is probably the only chance for certain minority races, which have virtually zero chance of finding a bone marrow match.'