Freezing umbilical cord cells could one day save the life of your children but the the process is far from cheap. Mother-to-be Kate Hilpern faces a modern dilemma

While I realise it's completely normal for first-time grandparents to want to buy something for the baby, I nearly choked on my roast dinner last Sunday when my dad suggested that he would like to finance the freezing of part of her placenta and umbilical cord. I had in mind something more akin to a cot or steriliser.

But my father had made up his mind that storing his granddaughter's cord blood - the baby's blood that remains in the placenta and umbilical cord after birth - would be the ultimate gift. Cord blood, I have since discovered, contains stem cells which are being used to treat blood-related disorders such as leukaemia and sickle-cell anaemia, as well as some immune and metabolic disorders. Some scientists also claim that cord blood could potentially be used to cure diseases such as Alzheimer's and Parkinson's and conditions such as diabetes, as well as diseases affecting the brain, heart and spine. "This is a present that could save her life," my dad announced proudly.

Should the need arise for my daughter - due to be born this month - to require a stem cell transplant at any point in her life, she could turn to cord blood stored in a public bank. But storing your own in a private, commercial bank provides a guaranteed match not only for you, but for your extended family.

Embryonic stem cells may also be an option for her, but these are controversial. What's more, Stephen Strom, an associate professor of pathology at the University of Pittsburgh, has discovered that cord blood stem cells do not generate the tumours associated with embryonic stem cells. "The placenta and umbilical cord appear to be a rich source for stem cells that are a non-controversial, and better, alternative to embryonic, and which have real potential to treat disease," he says.

The third possibility would be a bone-marrow transplant, an established and routine way of treating many diseases. The problem is that they are more likely to be rejected by a recipient's body than stem cells.

The practice of storing cord blood has already taken off in the States - in Pennsylvania, for instance, the issue has even entered into the state legislature: obstetricians who don't inform new mothers that this practice is possible are now at risk of being sued. That said, the reality is thatAmericans are more likely to go through with it if they're high-flying New Yorkers than if they're working class women from Alabama - not least because the cost, which is similar on both sides of the Atlantic, is anything upwards of £1,500.

Back in the UK, popularity is also growing. Type "cord blood stem cell bank" into Google, or look at the ads of a parenting magazine - you'll find numerous companies, many boasting over 10,000 customers.

"When our first daughter was born, we went without other things like flash prams. This was a priority. We'll do the same with this baby," says Rebecca MacCallum, 36, from Kent. "We don't have any hereditary illnesses, but why waste an opportunity to harvest my children's cells, when it can be done so easily?"

The "easily" bit is a relief to hear. I'm anxious enough about giving birth, without the added worry of painful surgery. But collecting the blood is non-invasive and risk-free to baby and mother and it only takes the midwife, nurse or obstetrician a few minutes to collect the blood. It's a routine procedure, performed when the newborn is jaundiced or the mother's blood group is Rh-negative or for blood typing.

The problem is that not all health professionals will oblige. My own NHS Trust has a specific policy demanding that "staff approached to assist women in obtaining such stem cells should decline to do so."

I'm left with two choices - either my husband rolls his sleeves up and steps in (which is more common than you might think, but not advisable) or I pay out an additional £200 for the stem cell bank to send out their own phlebotomist to do it.

My next dilemma is which stem cell bank to pick. George Macridis, managing director of Future Health, says that their forte is that they weed out stem cells immediately. "This has two benefits - it removes the red blood cells which can prove toxic for a recipient, and it takes up less space and is therefore easier to store," he says.

But Wayne Channon, chairman of Cells4Life, disagrees. "We store the whole blood. Otherwise, you may be throwing away something that might be useful in later life," he says.

Then there is the quandary of whether to opt for a private bank, which stores cord blood exclusively for use by your own family, or a dual public/private bank like Virgin Health Bank. "For some blood conditions, such as certain leukaemia, a transplant using a child's own blood may be harmful," explains CEO, Andrew Davis. "The stored stem cells may contain the same abnormality that caused the child to become ill in the first place. In this case, a donation from another source would be better. With our system, 20 per cent of the cord blood sample is kept privately for use by the family and 80 per cent is kept publicly, which improves the likelihood of all our members finding a match and enables parents to act ethically."

Shamshad Ahmed, managing director of Smart Cells International, isn't convinced. "The Virgin model may seem worthy, but saving 20 per cent of cord blood is a waste - you can't do anything with it," he insists.

Feeling even more baffled by my options, I approach some scientists specialising in stem cells, who will hopefully be more objective . Dr Ann Smith, however, is among those who won't talk to me unless I agree to quote them in their capacity as scientific advisers to private cord banks. Not so impartial, after all, then.

I finally strike gold with Dr Marc Turner, clinical director at the Edinburgh Blood Transfusion Centre and Honorary Consultant Haematologist at Edinburgh Royal Infirmary. He empathises with my bewilderment but advises me that stem-cell storage offers no guarantees. Though there have been more than 6,000 successful cord blood stem cell transplants worldwide - and 80 per cent of blood diseases are now treatable with cord blood stem cells - they are not a cure-all. "Beware of companies that claim they can cure Parkinson's or Alzheimer's. In the future, that may be the case, but for now, it's not," he says.

Professor Colin McGuckin, professor of regenerative medicine at the University of Newcastle, agrees. "If these banks really do want this to become a reality, they should put some of their profits into stem cell research, but many don't," he says.

Banks should also be honest about how long stem cells last, he says. "The oldest cord blood to be stored and transplanted successfully was 17 years old. Maybe next year we'll get to use blood that's 18 or 19 years old, but we can't be sure." Banks should also admit that stem cells may not be usable, he says. There may not be enough cells from one cord for a transplant, especially for an adult.

McGuckin warns that, though most UK stem cell banks have accreditation from the Human Tissue Authority, cowboysexist."I have helped close most of the bad guys down, but accreditation is not strict enough."

Among the big no-no's are companies that take longer than 48 hours from birth to get the blood to the bank. "If you leave blood hanging around, it clots, even with the use of anti-clotting agents, yet some banks still shuffle it off to be stored in America or South Africa," he says.

Always check who's on the advisory board. "Are they people who really know about cord blood or a bunch of financial people?" he says. "Also, avoid companies that demand money up front and offer no refund in the instance that not enough cord blood can be collected, which can happen."

As for the private versus public model and storing the whole blood versus just the stem cells, McGuckin says it's too early to be sure. "We won't know for another 10 or more years what's best," he says.

McGuckin's advice proves useful in sifting the wheat from the chaff. Most telling was one company that refused to answer any of my questions, simply stating that everything I needed to know was on their website - it wasn't. But though some banks ticked most of McGuckin's boxes, I'm still left feeling uneasy about the whole practice. The banks seem to use their marketing tactics to prey on the need for expecting parents to feel they're protecting their offspring's future. On balance, however, I have decided to gratefully accept what is, after all, an incredibly thoughtful and meaningful gift from my father - in the strong hope that it will never need to be used.

Before you bank on a cure... your homework with the stem cell banks:

* Is the bank accredited by the Human Tissue Authority and the Medicines and Healthcare Products Regulatory Authority?

* Is the bank completely honest about what diseases and illnesses cord blood stem cells can treat, or are they making claims based on what might be possible in the future?

* What happens if no stem cells are collected? For example, in cases where the baby is premature, the cord around the neck needs to be cut early to deliver the baby or you are delivered by emergency Caesarean section.

* Does the bank admit that your stem cells may not be usable or that there may not be enough for a transplant?

* Where are the stem cells stored and will it take longer than two days to get them to their destination?

* Are the people on the bank's advisory board medical or finance experts?

* Does the bank offer a refund in the instance that not enough cord blood can be collected?

* Does the bank make an additional charge to screen for bacterial diseases?

* Is anyone responsible for screening the blood to ensure that HIV/hepatitis-positive blood is stored separately?

* Who will own the cord blood legally?

* What will happen to the cord blood if the bank is no longer functioning in the future?

* Does the bank feed any of its profits back into stem cell research?