Volume 5, Issue 11 - January 2003

As we venture further into controversial embryonic research, we need public debate on ethics and aims, say scientists PETER SINGER and ABDALLAH DAAR.

Around the time the Harvard mouse case about patenting life was making headlines in Canada, we were hit with another mouse-research controversy. This second story dealt with a meeting last month in New York at which scientists discussed a proposal to create human-mouse embryos.

Will you pick up your morning paper in six months and read that scientists have grown a human brain in a mouse's body? Such an experiment would almost certainly not be carried out here. But these mouse tales highlight the need for Canada to better engage the public in decisions about ethically charged scientific frontiers.

The researchers proposed injecting possible human embryonic stem cells into an early mouse embryo; they'd then test whether the human cells were widely incorporated into the tissues of the developing mouse. In theory, embryonic stem cells are so versatile (this versatility is known as "pluripotency") that they can develop into any tissue in the body, hence their potential clinical usefulness. If the injected human cells are present in all the mouse's tissues, then they truly are stem cells. Because it would be unethical to do this experiment in a human embryo, the researchers want to use the mouse as a model.

But creating a mouse with a mixture of mouse and human tissues raises a familiar ethical balancing act. It again pits potential health benefits to patients against our concept of what it means to be human. Is a mouse with human tissues a mouse or a human? What if scientists create a mouse that produces human sperm, or a mouse whose brain is made up mainly of human cells?

Proponents say these images are misleading. They argue that the mouse experiment is not so different from current research where scientists put human genes into animals such as pigs to get around the problem of rejection in transplanting pig organs to humans. Besides, they say they would not allow the mouse embryo to develop to full maturity, or allow the mouse to mate.

By contrast, some of Canada's most knowledgeable stem-cell researchers warn that the mouse-human embryo experiment differs both in kind and in extent from previous research. They question the usefulness of this test and suggest using other, less controversial ways of achieving the same aim.

Canadian scientists Janet Rossant (who was at the New York meeting) and Ron Worton have come out against the proposed research; they're concerned it will trigger public backlash against more mainstream types of stem-cell research.

The experiment would also violate the Canadian Institutes of Health Research guidelines on funding stem-cell research, and would also likely violate provisions on assisted human reproduction in Bill C-13, currently before Parliament.

With unanswered ethical questions, regulatory and legislative prohibition, and the opposition of leading scientists -- clearly, Canada is not ready for the mouse- human embryo experiment. But it won't be the last example of a scientific advance that could benefit from broader public discussion.

How will we ensure that science and societal values remain aligned? So far, our approach seems to be to wake up to shocking headlines and knee-jerk denunciations from bioethicists. A better way to bring the public into ethical deliberation about biotechnology and genomics would be to engage Canadians on these cases in advance, and take into account their considered advice in formulating policy.

Already, the Canadian Institutes of Health Research have held public lectures and plan to emphasize more public engagement. The Canadian Public Health Association has conducted an extensive series of citizens' juries on the topic of animal-to-human transplantation. Some leading British scientists have gone to local pubs to discuss the social implications of their work, most recently the establishment of a large, population-genetic database.

A group of students at the University of Toronto Joint Centre for Bioethics has developed a teaching module to educate students about stem cells. The students play the roles of different stakeholders before a mock legislative committee, and then compare its legislation to Bill C-13. The module will shortly be disseminated to high schools throughout Canada.

But these moves are issue-specific. And the mouse- human embryo is only one of a long line of scientific projects that will require intense public engagement. We're not yet set up for the debate.

We need an established infrastructure for public engagement that can be deployed on the issue of the day. We must learn how to tap public assets -- such as science centres or public television -- to regularly engage the Canadian public on the ethical implications of scientific advances. Involving youth is especially important in shaping our future democracy.

Everyone should have a chance to decide whether the mouse-human embryo experiment should be performed -- rather than just read about it in the headlines.

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