We must stop trying to engineer nature

How suffering may be bad but the alternative could prove to be far, far worse

Any bereaved parent can tell you that nothing compares with the pain of losing a child. When my sister-in-law and her husband lost their first child - a baby just four months old - to cystic fibrosis, their world literally collapsed. Tests soon confirmed that both parents were carriers of the CF gene, so any future baby would have a worrying one-in-four chance of inheriting the condition. But reprod uctive technology offered a solution: embryos were created through in vitro fertilisation and cells were screened for the disease, after which only CF-free embryos were implanted. The process worked, and Sue and Chris now have two happy and healthy children.

This story illustrates how advances in medical knowledge can be of great benefit. But now consider another true story, this time from Texas in the United States, where the world's first human embryo bank was launched last year. For a mere £5,000, prospective parents can buy embryos via mail order, their genetic parents pre-specified for blond hair and blue eyes if necessary. The Abraham Centre of Life even boasts that all its sperm donors have doctorate degrees. Its director, Jennalee Ryan, is untroubled by the ethical issues raised by her company. "We are helping couples and putting good genes back into the universe," she boasts.

What these two stories show is that identical technologies - in this case, in reproductive medicine - can have good and bad applications. There is nothing new in this: the radiotherapy that cures cancer also allows us to have the atom bomb. Problems arise when society at large has insufficient expertise or foreknowledge to regulate, and if necessary stymie, new areas of scientific research as they come into being. The sit uation is made worse when the scientists in question aggressively push their opinions in the press, and seek actively to obscure the ethical issues that their work is raising in order to head off any potentially restrictive legislation.

A recent example is a group of senior scientists who wrote a furious letter to the Times in January, attacking government proposals to outlaw the creation of human-animal hybrid embryos on the grounds that this will hold up research into treatments for Alzheimer's and other neuro-degenerative diseases. As so often with genetics research, the potential to treat human diseases is wielded as an ethical cover to trump any legitimate wider concerns. Implanting human-cell nuclei in cow eggs may or may not eventually help people with Alzheimer's, but the implications of this technology are highly disturbing, even at this early stage.

Indeed, the whole science of genetics raises serious concerns about the future direction of human civilisation. As the American writer Bill McKibben has said, while the greatest macro-scale environmental challenge is global warming, the greatest micro-scale environmental challenge is genetic engineering. With each leap in technical understanding, scientists - and the corporations and governments that employ them - accumulate ever greater power, intentionally or unintentionally, over the future of the human species. Although crude eugenics and racial cleansing are generally held to have died out with the Nazis, the commodification of human reproduction could lead us blindly down the same eventual path.

Familiar moral lenses may offer little guidance. Stem-cell research and the cloning of embryos are most vociferously opposed by the pro-life and religious lobbies, but the purported rights of embryos are far from being the most important ethical issues they raise. The wider implications of human biotechnology are discussed in a thoughtful article in the March/April issue of World Watch magazine. As Dr Richard Hayes, director of the Centre for Genetics and Society in California, puts it: "The ability to manipulate human nature destabilises both the biological and social foundations of the human world."

As an environmentalist, I profoundly oppose these trends. Even allowing for their purported benefits - in the case of Alzheimer's, for example, or cystic fibrosis - the cure may end up being worse than the disease, as we find a society with increasing technological power over human life itself increasingly abusing what it means to be free and human. I want to see a society in which humanity stops trying to control nature, and learns to live within its physical, biological and spiritual boundaries. That does mean facing certain difficult realities, such as the fact that all of us will die one day. But nature shows us that death brings new life, and that this must be consolation enough. Suffering may be bad, but the alternative may prove to be far, far worse.

Mark Lynas has is an environmental activist and a climate change specialist. His books on the subject include High Tide: News from a warming world and Six Degree: Our future on a hotter planet.