Genetic engineering is a scientific development that involves the artificial manipulation of an organism's genes by using techniques such as molecular cloning and transformation in order to alter their nature and structure. Many of these transformations are achieved by manipulation of an organism's DNA, which effectively is the code inscribed in every cell to determine how it will function.

As with most scientific developments there are a number of arguments both for and against.

There has been a considerable amount of research into the genetic engineering of crops such as potatoes, tomatoes, soybean and rice, with the aim of obtaining new strains that have better nutritional qualities and better yields.

In a world where there is a continual need to produce more food; genetically engineered crops are being developed to grow on land that is currently not suitable for cultivation. By manipulating the genes in crops the aim is to improve their nutritional value, their rate of growth and their flavour.

Seeds can be engineered so that they are resistant to pests and can survive cultivation in relatively harsh climatic conditions. Biotechnology can also be used to slow down the process of food spoilage so that fruit and vegetables can have a longer shelf life.

Although on the face of it genetic engineering might appear to bring a number of very positive benefits, there is by no means a universal approval of this practice.

Greenpeace International is very firm in its opposition, pointing out that there is no adequate scientific understanding of the impact that genetically modified organisms might have on the world's environment and on human health.

Undesirable genetic mutations can lead to allergies in crops and critics believe that while genetic engineering might enhance taste and appearance of foodstuffs, it could also hamper the nutritional value. At the very least, in order to inform consumers, all foodstuffs or products that have been made from genetically modified food should be clearly labelled as such at point of sale.

Whole new substances such as proteins and other food nutrients can be produced as a result of genetic engineering. The genetic modification of foods can be used to increase their medicinal value, thus making available a range of homegrown medical vaccines.

Greenpeace maintains that commercial interests are the prime movers to introduce genetically modified organisms into the food chain and stresses that once these organisms have been released into the environment they cannot be recalled.

Genetic engineering has not just been limited to plants. Human genetic engineering is the specialised science of modifying the genotypes of human beings before birth.

The process can be used to modify certain traits in an individual. It can enhance positive traits, like increasing longevity and it can suppress negative traits, like preventing a child from developing certain genetic diseases in later life. It can also be used to obtain a permanent cure for certain dreaded diseases.

Critics also urge caution with respect to gene therapy in humans, pointing out that when one defect is treated, the therapy may lead to another. One cell can be responsible for many characteristics, so the isolation of the cells responsible for a single trait is by no means straightforward.

Genetic engineering can hamper diversity in human beings. Cloning can be detrimental to individuality and any such process would be prohibitively expensive to all but the very rich, making it an extremely divisive process.

The protection and respect of biological diversity is part of the global heritage of mankind, says Greenpeace. It is one of the world's fundamental keys to survival.

In certain circumstances it is clear that genetic engineering can work wonders, but the fact remains that it is a process involving the manipulation of nature. Millions of years have gone into making the world the way it is, but scientists now have the ability to dramatically change this at a stroke.

It is absolutely vital that genetic engineering should be subject to strict international controls and that any permitted genetic modification should only be carried out only in the most regulated conditions.