The rice . . . which has just been planted in Kansas and has been called 'the Holy Grail' by some GM enthusiasts . . . has been modified to grow two proteins found in human breast milk. The company that has produced it, California based Ventria Biosciences, says that it wants to use them in baby milk and rehydration drinks to fight the severe diarrhoea that kills some two million small children in the Third World every year. Its detractors dismiss this as window-dressing, citing a US Government disclosure that the proteins will be used in "yoghurts" and "granola bars".

Permission to grow the rice over some 3,200 acres of the state was granted two weeks ago by the Bush administration, in the teeth of vigorous opposition even from the US rice industry, which opposed the planting "in the strongest possible terms". Out of 20,034 comments on the plan officially received by the government, only 29 supported it.

Apart from its controversial use of human genes, the rice heralds a new generation of crops modified to grow drugs, in a process dubbed 'pharming'. While ostensibly beneficial, critics say that this will bring new dangers, because they may contaminate other crops. This could lead to people who should not be exposed to the drugs unwittingly eating them in their food. The leading technical journal, Nature Biotechnology, compared growing such pharmaceuticals in crops to "packaging pills in candy wrappers".

Plans to grow the rice commercially in California and Missouri were stopped because of fears that its genes would spread to conventional crops. It was allowed in Kansas because no other rice is grown in the state, making it unlikely that any cross-pollination would take place. But controls appear to be so weak that other, unapproved GM rice . . . supposedly kept isolated from conventional crops . . . has still become mixed with them, contaminating much of the US harvest.

The company says that the breastmilk proteins produced by the rice . . . lactoferrin and lysozyme . . . have been shown to fight diarrhoea. But critics point out that even the company's own studies suggest that they only shorten bouts of the disease by one and a half days, and add that the way to beat the disease in the Third World is to provide clean water and sanitation.

And they add that the modified proteins may also cause allergies and auto-immune disorders and nourish bacteria that cause meningitis.

Yesterday, Clare Oxborrow of Friends of the Earth said: "This product is both risky and completely unnecessary. The solutions to diarrhoea, are already out there and we do not need a genetically modified product, especially one that may risk public health."

Both sides of the controversy appear on the websites of the company, www. ventria. com, and of the most prominent opposition group: www. centerforfoodsafety. org.