Biologist James Sherley

Credit: MIT

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I've been a science writer for the last 18 years. If there's anything I've learnt it's that scientists disagree. On everything from global warning to the cause of Alzheimer's disease, there is vigorous and sometimes downright nasty feuding. It's always been that way.

The 17th century witnessed a great feud between William Harvey and Jean Riolin over whether the blood circulated or was merely absorbed by the organs. In the fullness of time Harvey's idea won out - not through argument, but by experiment.

Such is the nature of science.

That is why I am astonished at the language used by visiting associate professor James Sherley from the prestigious Massachusetts Institute of Technology (MIT). With the science of human embryonic stem cell research in its infancy and human therapeutic cloning still on the drawing board, he claims categorically that "embryonic stem cells provide no path at all".

This sort of certainty just doesn't jive with any science that I've ever encountered. He is also labouring under some illusion that he needs to campaign for the freedom of adult stem cell research in Australia. Adult stem cell research is alive and well in the country: the Australian Stem Cell Centre spends 30 per cent more of its budget on adult stem cell research than on embryonic studies.

Sherley makes many sweeping, indefensible claims. He claims that cloned embryos are always defective and that therefore any stem cells derived from them, or tissues derived from these embryonic stem cells will also be that way. But researchers at Lorenz Studer's lab at Cornell University working in mice have successfully treated mouse Parkinson's disease this way.

He claims that tissues derived from embryonic stem cells will form tumours, but that he won't have this problem with the adult stem cells he is modifying. But tumours are a big problem for any stem cell. Researchers using embryonic stem cells are making steady progress at winnowing away cancer cells. Recent reports using embryonic stem cells for retinal transplants or spinal cord injury have found the recipient animals tumour-free. On the other hand, the latest cancer research shows that the source of many common cancers is in fact adult stem cells.

Sherley claims that embryonic stem cells cannot be useful for tissue repair because adult stem cells are the ones that normally regenerate the body. But embryonic stem cells can be used to make adult stem cells. Rudi Jaenisch, also at MIT, used therapeutic cloning to give mice a graft of their own matching adult stem cells, which regenerated their bone marrow.

Sherley discards any claims that human embryonic stem cells can serve as valuable disease models. Yet Gabriela Cezar at the University of Wisconsin is now using human heart cells, made from embryonic stem cells, to test dangerous cardiac side effects from new drugs. Therapeutic cloning extends the possibilities to make embryonic stem cells from diseased patients. These cells might replay the course of the disease in the culture dish and would be used to study that disease and screen for drugs. Larry Goldstein at the University of California at San Diego plans to use stem cells from Alzheimer’s patients to find the first tell-tale signs of the disease and search for drugs that will halt it.

But it seems Sherley would, if he could, shut down the research of his American colleagues. He can’t because U.S. President George W. Bush has not made the techniques illegal; he has merely tried to choke the research by withholding U.S. federal funding.

But complete strangulation is what’s at stake in Australia. Sherley was in the country to press the Australian government to outlaw research that he does not agree with.

Scientific dispute is the norm, but deciding to outlaw research based on the beliefs of one group is something else. This is what the Soviet Union did to the science of genetics – they preferred Lysenkoism, which held that environment was all that mattered. They set their own science back by decades.

Fundamentally this situation is no different. Sherley has a belief that the cloned embryos under discussion are human beings. I have a belief that they are not: they are not 'beings' because they have no awareness, cannot suffer, indeed they have no potential to be a human being because they will never be implanted in a woman's uterus.

What they have is a human genetic blueprint - but then so do sheets of skin cells grown in a dish.

Sherley is driven by his moral position; so am I. My moral imperative is that the community and the many suffering individuals within it, is best served by first rate science whose truths are discovered through experiment not polemic.