"Some people feel that human embryos are people just like you and me. And so, for them, any research which involves their destruction (as most embryo research does) is not justified, regardless of the benefits which might come from it. I don't share that view."

Thousands of people die each year because they are in need of a donated organ. But there is an acute shortage of organs. Even when a suitable donor, with a compatible tissue type, is found, the patient is faced with a regime of drugs to suppress their immune system until the organ is accepted by their body.

Thousands of others suffer from diseases of the nervous system, such as Parkinson's and Alzheimer's disease. There is, as yet, no cure for these diseases. When brain cells die, as they do in such diseases, no new ones grow to replace them.

A future treatment for various types of human diseases lies in stem cells. These cells are ones which are capable of replicating themselves and of developing into different cell types. There are different types of stem cells, some a little more specialised than others. Less specialised ones, which can develop into a limited number of cell types, are found in everyone's body. But there aren't many of them and they are difficult to isolate.

Embryonic stem cells and therapeutic cloning

A more plentiful source of stem cells is the early human embryo. Embryonic stem cells are capable of developing into any one of the 216 different types of cells in the human body. Encouraging research to date suggests that scientists may be able to isolate these embryonic stem cells and to encourage them to develop into a particular cell type.

Those cells could then be used to treat patients who, because of a disease or an accident, are in need of cell therapy. But, although embryonic stem cells provide a source of new cells for treatment, most need, just like donated organs or blood, to be compatible with the recipient. Even when the stem cells do match the recipient's, drugs need to be used to avoid the risk of an immune rejection.

One way of getting around this problem would be to grow embryonic stems from the patient's own body, thus avoiding any risk of rejection. But since embryonic stem cells are not present in the adult body, a new embryo would need to be created which is an exact genetic copy of the patient. This is where cloning comes in.

The cloning technique which created Dolly the sheep was designed to produce a cloned lamb. But the same technique could be used in humans, not to produce a cloned baby, but to create a cloned embryo which is not transferred to the womb and is not, therefore, allowed to develop into a fetus.

Instead, embryonic stem cells could be derived from the early embryo and the resulting cells could be used to treat the patient. Someone with liver disease, for example, could be treated with liver cells taken from their own body.

It may, in the future, be possible to avoid making cloned embryos by finding ways of growing embryonic stem cells directly from a patient's own cells.

Whilst this is a goal, it will not be possible for some years to come. In the meantime, embryos provide the best source of stem cells for possible cell therapies.

Some people feel that human embryos are people just like you and me. And so, for them, any research which involves their destruction (as most embryo research does) is not justified, regardless of the benefits which might come from it. I don't share that view.

The moral philosopher Mary Warnock once said 'Any fool can see that life begins at conception. It's when life begins to matter morally that is important.' For most people, life becomes more important as it develops from conception to birth. In that sense, a child or an adult is morally more important than a fetus or an embryo.

And so, if an early human embryo can be used in research or treatment which will benefit society, it is ethically right to do so. Human embryo research has already been responsible for a number of advances in medicine: fertility treatments such as in vitro fertilisation and genetic technologies such as embryo screening. If embryo research in the future can be used to help develop stem cell therapies, then it is our responsibility to explore it as a possibility, even if we look at other options at the same time.

Treatments for Parkinson's or diabetes or muscular dystrophy cannot come a moment too soon.

Reproductive and therapeutic cloning are not the same

Many people opposed to human embryo research have lumped together the creation of cloned babies and the use of cloned embryos for research.
By doing this, they hope to capitalise on people's objections to producing cloned babies (reproductive cloning) and trick them into believing that cloned embryo research (therapeutic cloning) is equally bad. But these two activities are very different in their goals and should be considered separately.

Is there a slippery slope to cloned babies?

Some have said that therapeutic cloning and reproductive cloning might be different, but because they both involve the creation of a cloned embryo, one might lead to the other. For them, cloning for stem cell therapies is a slippery slope on the road to reproductive cloning. Of course, every new technology has the potential to be misused or even used to cause harm.

This is a risk we always take. But if the research or the technology is of real benefit, it is often a risk worth taking. I think the same can be said for stem cell therapies. It is worth taking a tiny risk of abuse because the benefits that could come from this research promise to be so great. But it is also worth remembering that embryo research is not new. It has been performed for a number of years under the watchful eye of professional and government committees.

In all that time, a researcher using human embryos has never been prosecuted under the law. Many activities, such as mixing the egg and sperm from different species, have been possible for decades, but they have not been performed by those carrying out research on human embryos.

And so, human embryo research and the scientists who carry it out have a good track record and can, I think, be trusted with stem cell research.

Doing nothing is unethical

In the debate about cloning and stem cell research, some have suggested that doing nothing is the best way of ensuring that no harm is caused to anyone. But this is not true.

Doing nothing is not neutral: it needs to be justified just as going ahead does. But I think, when we balance the possibility of harm with the likelihood of benefit to mankind, the message is clear.

We must proceed with this research for the sake of the people who need these new treatments. To do nothing would not just be overcautious - it would be unethical.

Further information about the Progress Trust visit their website at http://www.progress.org.uk