Since the discovery of human embryonic stem cells in 1998, stem-cell science has been subjected to trial in the court of public opinion. In that court scientists have been called upon as expert witnesses. It is a position of influence and power. For the lay public the arcane knowledge of scientists makes them as daunting and unchallengeable as high priests.

Over the past 12 months, Australia rumbled through its second-round debate on embryonic stem cells and therapeutic cloning. This ultimately led to the lifting of the ban on therapeutic cloning, and a slight relaxation in the law prohibiting the creation of embryos for research. During the course of the debate, we saw many scientists taking the public podium, expressing their expert opinions in newspapers, radio, TV and public lectures. Perhaps now, as the dust settles, it is an opportune time to ask how well scientists performed that public duty. Did they live up to public trust or did they abuse it? Did they fudge the boundary between expert analysis and personal opinion? Did they fail to disclose potential conflicts of interest, religious or commercial?

Scientists in the public spotlight walk a difficult tightrope. Real science provides few definitive answers. Yet in the public arena, the fuzzy grey language of science needs to be sharpened into the black and white of media speak. The risk of that sharpening is overstatement. Certainly, scientists have been criticised for ‘hyping’ the potential of stem-cell science. And where those scientists have had associations with stem-cell companies, the accusations of ‘conflict of interest’ have flown thick and fast. But over the past year we saw scientists overstep the mark in a different way.

It seems to me that all scientists should adhere to some basic tenets when they address the public. The first is the limitations of science itself. Though scientists may be seen as high priests, science is not in fact about prophesy, and scientists are not able to divine the future. By definition, the long-term results of research are unknowable. Science is replete with surprise and serendipity, where breakthroughs end up coming from left-field, like Barry Marshall and Robyn Warren’s discovery of stomach bacteria which led to a spectacularly successful cure for ulcers. In the case of medical research in particular, what we do know is that the success rate is abysmal. Ninety per cent of drugs that enter early-stage trials never make it to the clinic. The key to success in science is to cast the net as widely as possible.

So a scientist has no place prophesying that research using embryonic stem cells and therapeutic cloning will never succeed in producing novel cures, while blithely stating that adult stem-cell research will. This is the gist of the expert opinion we saw from James Sherley, an associate professor from MIT, who was invited to tour Australia by the organisation Doctors Against Cloning. He gave voice to his opinion in public lectures (including one at Parliament House, Canberra) and newspapers, as well as appearing on radio and TV. Sherley also offered extensive ‘expert’ evidence at the October parliamentary senate enquiry. (Back at MIT, Sherley is now on a hunger strike in protest at failing to receive tenure, which he claims is because he is a black American.)

In Australia, Sherley abused his status as a ‘respected’ scientist by fudging the boundary between expert scientific appraisal and personal belief. Sherley did not assist the public to weigh his views against those of other scientists by declaring his potential religious conflicts of interest. Sherley’s public talks were replete with religious rhetoric but his religious affiliation was not made clear. For instance, his categorical statement that an embryo has an equivalent status to a human being is his personal view, not a scientific or legal fact. This is not to say that a person with a religious affiliation is not capable of being objective about scientific evidence. But the same is true for a person with financial interests in a stem-cell company. If scientists are being trusted to give expert opinion on science, then the public needs to know what potential conflicts of interest may be colouring their rendition of the evidence.

But scientists also prophesied in other ways that I personally found discomfiting. The Lockhart Review and Senator Kay Patterson’s Bill initially recommended allowing the use of animal eggs as a vessel to attempt somatic cell nuclear transfer (SCNT) – the technical name for therapeutic cloning. While therapeutic cloning will ultimately require the use of human eggs, the technique is yet to be mastered.

Given the preciousness of human eggs, in this experimental phase it makes sense to allow researchers to practise with animal eggs. Chinese researchers, for instance, reported success with rabbit eggs. However, in the public arena, politicians scored points against Patterson’s Bill by conjuring alarmist sci-fi scenarios of human–animal chimeras, such as ‘rabbit man’. (In fact, these chimera embryos could only have a transient existence on the laboratory benchtop as they are not viable.) Some scientists added ammunition to the opponents’ camp by expressing their scepticism that animal eggs would work in human SCNT, or that their use was unnecessary. At the 11th hour, the clause about using animal eggs was dropped from the Bill. And the Bill finally passed in the senate: by one vote! Some will view the jettisoning of animal eggs by scientists as a tactical victory: better to lose a battle and win the war, they say. Personally, I see it as a failure of reason and science.

Scientists may have overstepped the boundary of their duties as scientists, but politicians have been worse. Politicians are not required to shed religious or moral convictions on entering politics. But to what extent is it acceptable to pursue personal religious agendas while serving as parliamentarians? It is a grey area, no doubt. Surely the boundary would be when those personal agendas start interfering with the letter and spirit of the democratic process.

That boundary seemed very close to being transgressed last June, when Howard’s cabinet, strongly weighted by religious conservatives, voted to scuttle the recommendations of the Lockhart Review to lift the ban on therapeutic cloning without a full discussion by the party at large.

That boundary seemed very close again during the Senate Committee Inquiry conducted in October, after Senator Patterson’s Bill to implement the recommendations of the Lockhart Review had been tabled for senate debate. One would expect the senators conducting these enquiries to behave in an impartial manner in examining the ethical and scientific material that had been submitted to the committee. Instead, the undisguised prejudice and downright hostility of some of the senators made a mockery of the inquiry process. Some of the senators badgered disabled proponents of therapeutic cloning with a demeanour that was akin to that of a TV drama courtroom prosecutor. For instance, spinally injured research advocate Joanna Knott was badgered with questions about the status of an embryo at different ages and what was to stop a ‘slippery slope’ leading to demands for increasingly older embryos for research. As Knott wrote to me: “I’m not an embryologist; I felt like I was on trial.” Dr Paul Brock, an educator and one-time Marist brother who is crippled by motor neurone disease, was appalled by the tone of some of the questions. As Brock wrote to me: “In my professional career I have been involved in quite a few parliamentary inquiries, on both sides of the ‘table’. I am used to chairs adopting a relatively disinterested approach to witnesses. For example, when I appeared before the Lockhart Committee, nothing said by Justice Lockhart or any of his other five colleagues on that Committee gave me any idea whatever as to what position or positions they were taking about therapeutic cloning! By stunning contrast, never have I ever seen – no less been subjected to – such partisan belligerence within the context of a government/parliamentary inquiry as demonstrated by Senator Humphries and Senator Fierravante-Wells.”

Perhaps in the quiet before the next storm, some reflection on the part of politicians and scientists on the appropriate way to disburse their public duties is in order.

Dr Elizabeth Finkel is a correspondent for the US magazine Science and a contributing editor of Cosmos magazine. She is also a frequent contributor to ABC radio’s Ockham’s Razor, the Science Show and the Health Report. She has won numerous awards for journalism, including the Michael Daley award, MBF awards and Amgen awards. In April 2005, her book Stem cells: controversy at the frontiers of science was published by ABC Books. It won the Queensland Premier’s Literary Award, and was shortlisted for the Victorian Premier’s literary award. She has a PhD in Biochemistry from the University of Melbourne and completed five years of postdoctoral research at the University of California in San Francisco. After returning to Australia, Elizabeth traded the laboratory bench for the laptop. She writes for both the scientific and lay audiences.