The Ministry of Health's investigation into a controversial US-backed genetically modified rice research project in Hunan province raises a wider set of questions than just the use of GM seeds to increase crop yields, because the researchers are alleged to have fed students GM rice as part of an experiment without their or their parents' knowledge.

The research was backed by the US National Institute of Health and the US Department of Agriculture, according to an article published in the August edition of the Journal of Clinical Nutrition.

The answers to all the questions that the Ministry of Health-ordered investigation raises are not yet known. GM seed makers say there is no proof that their seeds will harm human health, but a host of geneticists and ecologists across the world say there is no proof that GM seeds will not harm humans.

The battle lines for and against GM seeds were first drawn in Europe in the late 1990s. Activists in Europe claimed that GM seeds were unsafe for human consumption and damaged or destroyed other seeds and crops. Soon the opposition to GM seeds spread to other regions, and justifiably so if we look at what happened later to farmers in countries like India who planted GM seeds.

For all the claims of GM seed makers, especially Monsanto, cotton crops have been failing with eerie regularity in India. A country that first cultivated cotton more than 7,000 years ago (in what is now western Pakistan) and spread the skill of making cotton yarn to the Mediterranean and hence the rest of the world has seen more than 200,000 farmers commit suicide in the past decade. The farmers committed suicide because they were neck deep in loans, which they were forced to borrow to overcome successive Bt cotton crop failures.

The vicious circle the farmers were caught in - of using more expensive Bt cotton seeds and larger amounts of fertilizers and insecticides to increase their yields - was too much for them to sustain.

Thousands of kilometers away, Mexico, which gave corn to the world, has to import the bulk of its corn supply from the US today despite using GM seeds. If that was not enough of an irony, scientists in the US now say that corn rootworms might have developed resistance to GM corn, and the US Environmental Protection Agency says it plans to investigate.

Until the first half of the last century, seeds were overwhelmingly the property of farmers and public-sector plant breeders. But in the decades that followed GM seed makers have used intellectual property laws to commercialize seed supply throughout the world and are aggressive in their designs and sales strategies to maximize their profits. The top five GM seed makers - Monsanto (US), DuPont (US), Syngenta (Switzerland), Groupe Limagrain (France) and Land O' Lakes (US) - control 57 percent of the global seed market. Since the mid-1990s, Monsanto, Syngenta, and DuPont along with Bayer and Dow have bought up more than 200 other companies to become dominant players in the seed market. Can there be a better example of oligopoly?

GM seed makers jump in with "help" when crops fail in a country because of natural or human factors. They offer GM seeds as the panacea for all agricultural ills, only to milk farmers of their last penny, for once a farmer plants GM crops there is no going back to using normal seeds simply because natural seeds cannot yield anywhere near a healthy harvest on a piece of land where GM seeds have been planted.

The world may keep debating the pros and cons of GM seeds. But the farmers who have paid with their lives for using GM seeds have their own tale to tell.

Hopefully, the Ministry of Health has taken these factors into consideration while ordering the investigation into the controversial GM rice research in Hunan.

The author is a senior editor with China Daily. E-mail: oprana@hotmail.com