Miracle or murder?
This week, an Irish university became the first in the country to proceed with embryonic stem cell research, a science hailed as medicine's Holy Grail yet mired in controversy at every step
To some, it is a grotesque attack on the sanctity of human life; to others, a beacon of hope in the fight against debilitating conditions as disparate as cancer, Alzheimer's and spinal paralysis.
Human embryonic stem cell research has been steeped in controversy for more than a decade, but in the laboratories of University College Cork, there were celebrations this week at the news that the pioneering science would now be authorised on campus.
As the first university in the Republic to carry out the research, UCC will be at the cutting edge of a revolutionary technique which has the potential to redefine 21st- century medicine and eliminate a plethora of life-threatening diseases. The men and women who will devote their lives to the research believe that the benefits far outweigh the disadvantages, but opponents say it is tantamount to murder because stem cells come from discarded embryos, each of which has the potential to become a fully fledged human.
It is exactly 10 years since James Thomson, a biologist at the University of Wisconsin, in the United States, made history when he successfully removed stem cells from a batch of frozen human embryos. These microscopic clumps of tissue, smaller than the full stop at the end of this sentence, came from embryos left over by fertility clinics but in the scientific world they held the key to unlocking cures for some of humanity's most devastating diseases.
The discovery came on foot of the news that a sheep named Dolly had become the first cloned mammal, opening up the prospect of a brave new world of scientific possibilities where human body parts could be grown and tailored to match an individual's unique tissue type.
But even Thomson accepted his breakthrough posed huge ethical dilemmas. In 2007, he told the New York Times that if human embryonic cell research does not leave you at least a little bit uncomfortable, you have not thought about it enough.
The wonder of stem cells lies in their ability to divide. They can make other cells exactly like themselves and turn into any of the 220 types of cell in the human body from brain to skin. They are the building blocks of human life, continuously re-stocking their supplies when lost or damaged by illness, injury or age.
Human stem cells come in two forms: embryonic stem cells (hESCs) which grow within days of conception and produce all the body's tissue, and adult stem cells found in the mature tissue of children and adults, such as bone marrow. What makes embryonic cells special is their flexibility and, unlike adult cells, they can reproduce themselves, meaning they could potentially be used to replace damaged and diseased cells in the body.
Adult stem cells are already used to treat diseases such as leukaemia and heart disease but scientists believe their younger counterparts offer the chance of miracle cures, even for the terminally ill. While the new science has claimed no cures or treatments yet, and is not ready for use on patients, hardly a week goes by without the publication of a new academic paper announcing the latest development in stem cell research. In 2001, progress was stalled following a decision by US President George Bush to ban federal funding of most human ESC research on the grounds that the destruction of embryos was immoral no matter what the health benefits.
Until this summer, only one company had made any significant headway.
In 2005, Californian biotech firm, Geron generated a wave of hope among victims of spinal injuries when its scientists made paralysed rats walk again after injecting them with hESCs. The study is still at laboratory stage, but human trials could begin next year if the US Food and Drug Administration gives its approval.
This August marked another milestone in stem cell research when scientists found a way of growing large quantities of blood in the lab using hESCs, potentially making blood donations and shortages a thing of the past.
Attempts to make blood from adult stem cells have been unsuccessful, but this study showed that up to 100 billion red blood cells could be created from a single plate of embryonic cells.
The New Scientist described the discovery as proof that hESCs were showing promise at last: "At long last, researchers have managed to turn ESCs into something with obvious practical potential: an inexhaustible supply of red blood cells, which could in the future be transplanted into anyone, irrespective of their blood type."
Today, stem cell research is bringing new insights into the treatment of a whole range of diseases. Some intriguing new studies suggest it could unlock the secrets of why cells turn cancerous. A Californian company is seeking to treat people with eye defects using hESCs while scientists studying diabetes are making progress transforming embryo cells into insulin-producing cells.
There are also signs of hope in treating heart disease with the discovery of a new group of stem cells that could regenerate injured heart tissue and scientists in the US have grown new prostate glands in mice using them.
But groups opposed to the use of embryos for research claim that a dramatic breakthrough last November makes their destruction unnecessary and unwarranted. In a development that caused elation in the world of medicine, a team of scientists in Japan announced that they had found a way of reprogramming adult skin cells to behave like embryonic ones, without having to make or destroy any embryos.
This raised the possibility that one day it might be possible to reprogramme a patient's own cells into human embryonic cells, and in turn into heart, muscle or any other kind of tissue. Being able to recreate a person's own adult cells would allow doctors to work without fear of rejection by the immune system.
Since then, American scientists have used the technique to develop nerve cells, but it is still unclear as to whether these reprogrammed cells are as reliable or carry the same therapeutic potential as embryonic cells. Despite the Japanese achievement, the consensus in the world of science is that the use of embryo cells should be allowed to continue.
The fact that no legislation exists in Ireland on the status of embryonic stem cells has allowed UCC to go ahead with its research but pro-life groups have accused the college of hypocrisy and being complicit in the "murder of embryos".
The college has vowed that its research will be carried out under strict ethical guidelines. Each project must first seek the approval of the University Research Ethics Board and scientists will only be allowed to work on embryos imported from approved sources in other jurisdictions.
For the millions of people suffering from incurable illnesses who see stem cell research as their lifeline to a cure, the study of science in Ireland took a huge step in the right direction this week.
But in a country where the right to life of the unborn evokes such bitter debate, the practitioners of this controversial technology face an uphill battle at every turn.