She could never have imagined that in less than two years her decision would help to save the life of the Canadian infant as he battled against eye cancer.

Jesse’s story is expected to hasten a mini-revolution in medical care, as tens of thousands of parents seek to store powerful regenerative cells from their babies’ umbilical blood as a biological insurance against future disease.

A new generation of private blood banks is springing up across America to enable parents to store umbilical cells for a guaranteed perfect match should their child ever need blood or a bone marrow transplant.

At the Arizona-based Cord Blood Registry (CBR), 30 Britons are among the 38,000 parents who are keeping umbilical blood frozen in liquid nitrogen tanks. More than 100,000 parents have gone to other banks.

Umbilical blood is rich in stem cells, the engines of healthy human growth that develop in the embryo and multiply rapidly, manufacturing blood and building the body’s immune system. Researchers believe that stem cells may prove effective in the treatment of a wide range of diseases, including Parkinson’s, Alzheimer’s and arthritis.

Controversy over cloning and abortion is stalling the use of cells from embryos, but interest is increasing in umbilical cord blood, which has already been used in more than 2,000 American transplants with a high rate of success. Most of those involved patients using donated blood from family members. Cases of children who are saved by their own blood are still so rare that some doctors worry that parents are being lured into expensive private schemes to store blood that their sons and daughters will never need.

Yet Farquharson, a former shipping clerk from Bolton, Ontario, has no hesitation in urging parents to follow her example.

“If you passed up the chance to save that blood and something happened,” she said, “it would just be an amazing tug on your heartstrings. They gave Jesse a 0% chance of survival. But we had his cord blood and he’s still alive.”

Jesse was four months old when his parents were told that he had a brain tumour which would lead to blindness. Then specialists diagnosed bilateral retinoblastoma, a rare eye tumour.

The diseased eye was removed in November 2000 but the cancer was found to have spread to Jesse’s spinal fluid. An aggressive chemotherapy programme aimed at both the eye and spinal cancers appeared to have been successful, but Jesse’s immune system was destroyed. At risk of death from the slightest infection, he underwent a bone marrow transplant last year using the stem cells his parents had saved.

To the family’s delight, the transplant was a huge success. The compatibility complications that often arise with donor marrow or blood never occurred. Jesse’s healthy umbilical cells regenerated swiftly, rebuilding his immune system, and although he is now blind he has returned home with his parents.

“Everyone says he is a miracle child,” said Farquharson.

The commercial blood banks specialising in umbilical cells have seized on this and a handful of similar cases to promote a storage service that can cost parents up to £1,000 in initial charges, with additional annual fees of up to £70.

One researcher recently calculated that there was a one in 1,400 chance that a child’s stored umbilical cord blood might be used to help a sibling or parent who was ill; and a one in 2,700 chance that a baby would need its own blood.

For some parents, as they ponder a blood storage service that costs about the same as a home computer, the odds are not too long.

“If those cells are there when you need them,” said Farquharson, “you’ll never regret your decision.”