Below we outline the key facts and some of the arguments in the debate for and against GMOs:
- Genetic modification is a technique where individual genes can be copied and transferred to another living organism. It changes the genetic make-up by adding or removing specific characteristics.
- Biotech crops are plants that have been genetically altered to improve resistance to diseases caused by insects or viruses and to increase tolerance towards herbicides or extreme weather.
- One of the best-known examples is gene-modified soy which is tolerant to the herbicide glyphosate, allowing for better weed control and fewer lost plants.
- The United States is the world leader in biotech crops, with gene-spliced varieties accounting for 75 percent of US soybeans, some 70 percent of cotton and 35 percent of corn.
- Before the EU's decision to allow imports of Bt-11 maize in May 2004, the first new GMO approval since 1998, the EU had not permitted experimental or commercial growth of any new gene crops since October 1998. Then, 18 gene plant varieties were already approved, including maize, rapeseed, chicory and soy.
- But as consumer fears grew in the late 1990s, EU states including Austria, France, Greece, Italy and Luxembourg banned already approved gene crops.
- EU governments also restricted field trials, and between 1998 and 2002 the number of trials dropped by nearly 90 percent.
- The United States, with Argentina and Canada, decided to challenge the de facto EU ban within the World Trade Organisation. It said there was no scientific basis for the moratorium and that it was illegal.
- Supporters of GMO technology say it will lower costs for farmers, increase crop yields, decrease the need for chemicals and help to feed millions in a hungry world.
- Some proponents argue the world has two choices if it keeps growing and wishes to avoid food shortages: either alter the genetic makeup of crops so that they increase production from the same space or clear more savanna and rainforest, thus reducing biodiversity, to expand the world's productive farm land.
- Opponents are concerned about the health risks and the threat to the environment, saying not enough studies have been done to prove it is safe and will not harm natural species. They also fear the impact on biodiversity and control of crops by large corporations.
- Opponents are also concerned about the extent to which commercial interests are driving the science and the regulatory system. "A key question remains why such an enormously powerful technology, about which there are still deep uncertainties, has been introduced so rapidly without meaningful public consultation," says GM Watch on its website. - Green groups say there have been no long-term health tests on GMOs, claiming that biotech plants can contain antibiotic resistant genes which may be able to pass on this resistance to humans, and insects may also develop resistance to GMO toxins.
They warn of the dangers that GMO plants can pose to traditional and organic agriculture with the risk of cross-pollination and long-term contamination of soil.
"Genetic engineering has not been assessed against alternatives such as organic farming," UK-based green group Five Year Freeze said on its website.