Cardinal Renato Martino, president of the Pontifical Council for Justice and Peace and the keynote speaker at a conference in Croke Park, Dublin, next Thursday, is one of the main proponents of GM food. He sees it as a way of tackling world hunger. An endorsement by the Vatican of genetically modified organisms would have a profound impact on global discussion of the issue, as there are more than one billion Catholics in the world.

Together with the Pontifical Academy of the Sciences, the US embassy cosponsored a seminar at Rome's Gregorian University in September 2004 entitled Feeding the World: The Moral Imperative of Biotechnology. The speakers were avid supporters of GMOs; the message of the day was that opponents of GMOs were not merely ignorant of the science involved but were driven by questionable motives.

Critics question the "feed the world" argument by pointing to the fact that the main threats to the food supply of the poor in this century will be global warming and the destruction of biodiversity. The melting of the glaciers on the Himalayas will affect the meltwater of the great rivers of Asia which supply water for one-sixth of the world's population. And President George W. Bush has repudiated the Kyoto Protocol and has refused to sign the UN Convention on Biodiversity or the Cartagena Protocol on Biosafety.

Bishops in Asia, Latin America and Africa have been critical of GMOs. They believe that banishing hunger has more to do with changing the social and economic inequalities which create poverty than with claiming that a "magic bullet" technology will feed 850 million poor people worldwide. Brazil is the fourth-largest exporter of food in the world and yet 35 million people go to bed hungry every night in that country.

Cardinal Napier of Durban has written that genetic engineering is an imprecise technology and that the long-term health effects of consuming GMOs have not been fully assessed. Consequently, because we do not know whether there are serious risks to human health or to the environment, to produce and market genetically modified food is morally irresponsible.

The precautionary principle should apply here, as it does in medical research. The Pontifical Council for Justice and Peace held a two-day Seminar on GMOs in November 2003. The majority of those invited were pro-GMO. Nevertheless, in a subsequent press conference, the cardinal stated that the Vatican had taken no position on GMOs.

This seemed to change in 2004 with the publication of the Compendium of the Social Doctrine of the Church. First of all, nine paragraphs in the document deal with biotechnology. This is surprising considering that global warming and the extinction of species only merit half a paragraph each.

The text seems to imply that, with the necessary cautions, the church is in favour of plant biotechnology. Paragraph number 473 states that, in effect, nature is not a sacred or divine reality which man must leave alone: "The human person does not commit an illicit act when, out of respect for the order, beauty and usefulness of individual living beings and their function in the ecosystem, he intervenes by modifying some of their characteristics or properties."

When these contradictions were brought to the attention of the secretary of the Council for Justice and Peace, Bishop Crepaldi, he insisted that the world does, in fact, depend on biotechnology.

Although far-fetched, the biotech companies often use this argument to claim that their technology is in conformity with natural breeding processes.

In reality, biotechnology, as currently understood, always involves the transfer of genetic material between different species. This was not possible until the mid-1970s.

The pontifical council has an obligation to clarify its position on the use of GMOs. Before it reaches a decision, it must address the issue of patenting seeds and other living organisms - 2005 was the Year of Rice, during which the rice genome was sequenced. This was a wonderful breakthrough for rice production. Almost immediately, giant agribusiness corporation Syngenta filed for 15 global patents on genes and gene sequences. Patenting is about privatising the living world for the benefit of the rich.

This is a most worrying development, as it will give a handful of global corporations control over the seeds of the staple foods of the world. And it is surely a prescription for hunger, malnutrition and death. lt would also seem to be at odds with the Christian faith, which holds that a loving God created our living world and wishes it to be shared generously with all the people and creatures inhabiting it.