Leading article: Science, genes and the food on your plate

IT IS all too easy to take fright at the idea of genetically-modified food. The simplest take on the subject would be to condemn it out of hand as a sinister plot by multinational corporations, cynically prepared to meddle with the essence of life for the sake of profit. That would be wrong. Genetic engineering promises great benefits, and there is nothing wrong with anyone making a profit from the use of new technologies. And yet the decision by education authorities to ban genetically-modified food from school meals, which we report today, is the right one.

Let us first dispel some anti-scientific fears clouding this debate. The idea of tampering with genes for nefarious ends was embedded in science fiction as soon as the biochemistry of DNA was understood. Today, it is the basic storyline of such cheap children's animated drama as Street Sharks, in which four teenage boys have been turned into half-humans, half-sharks by mixing the two kinds of DNA.

More generally, humanity's capacity to be afraid of the "unnatural" is almost as great as our desire to control nature. It needs to be recognised that almost all our food is unnatural in that it has been bred selectively, cultivated and treated with pesticides and chemicals. Selective breeding has already produced disease-resistant strains of crops, and the more productive crops which led the green revolution in the developing world.

That said, genetic engineering is qualitatively different from what went before. By altering the genetic structure of plants and animals directly, instead of by breeding, entirely new organisms can be created. Some of the products of the new bio-technology could be more "natural" or environmentally sustainable than the products of the old chemistry lab. Genetically-modified crops might need fewer chemical fertilisers, for example, and there are many other possibilities for reducing reliance on chemicals which could damage human health. It has been suggested that naturally-occurring viruses could be "supercharged" by genetic manipulation in order to control crop pests without using chemical pesticides.

Equally, however, there is a danger of raising the stakes in an agricultural arms-race. If disease-resistant crops cross-pollinate with weeds, the weeds themselves will become hardier and more likely to choke the crops. And there is a more insidious threat from genetic manipulation, in that it is working at the limits of human knowledge, and may have consequences which cannot be understood or guessed. It may simply be beyond our ability to make a sensible risk assessment. It is not alarmist to make an analogy with BSE - the transmission mechanism to humans is still not fully understood, decades after such diseases were identified.

The main danger of genetic tinkering is in the unpredictable effects on the food cycle when modified plants interbreed with other plants. But it would be wrong to argue that eating the products of genetic manipulation, such as modified soya, is safe, because the food consists only of proteins which occur naturally, and there is no method by which the modified genetic information can be transmitted to the consumer. Those were the kind of reassuring observations made about BSE before the science was better understood.

There are grounds for caution, therefore, and the crux of the issue is openness. If Monsanto is so confident its genetically-modified foods are so harmless, then why not label them? That should have happened from the start, and American soya supplies are already mixed and unidentifiable.

Information is our best protection. It is also in Monsanto's commercial interest. It would be expensive to keep modified foods separate from the unmodified, but if genetically-engineering food is so good for us, it would be in Monsanto's interest to shoulder the burden now. The alternative is that consumers will become suspicious about the company's motives, and governments will force producers to label modified food in a context which would make consumers more likely to avoid buying it.