Monsanto has denied that health problems in Argentina are caused by its pesticides, insisting that its products are safe. It rejects an AP report that it is to blame for an increase in cancer rates and birth defects.

Reacting to an AP report investigating the effects of Monsanto products in Argentina, Monsanto called for more government control and attacked the credibility of the research.

"If pesticides are being misused in Argentina, then it is in everyone's best interests – the public, the government, farmers, industry, and Monsanto – that the misuse be stopped," the St. Louis, Missouri-based company said.

Monsanto also reiterated that glyphosate – a chemical used in the pesticide Roundup – was proven to be safe. Company spokesman Thomas Helshcher dismissed the correlation between use of pesticides and a rise in ill health as lacking in validity.

"The absence of reliable data makes it very difficult to establish trends in disease incidence and even more difficult to establish causal relationships. To our knowledge there are no established causal relationships," Helscher said.

AP carried out interviews across Argentina with doctors and people who had suffered harmful effects from Monsanto’s pesticides. They found that it many places regulations were flouted by farmers and pesticides were used within 30 meters of populated areas, instead of the recommended minimum of 500 meters.

More worryingly, the study found that in the soy-producing province of Santa Fe in northern Argentina cancer rates were two to four times higher than the rest of the country. Furthermore, Researchers also found high rates of thyroid disorders and chronic respiratory illness.

Argentina is the world’s third-largest producer of soy, and virtually all its soy crop is grown from genetically modified seeds.

In spite of Monsanto’s claims that the chemical glyphosate is proven to be completely safe, the study found evidence it can be harmful.

Molecular biologist Dr. Andres Carrasco, of the University of Buenos Aires, injected small samples of the chemical into embryos, which caused a change in retinoic acid level – a substance fundamental for keeping cancer in check.

Researchers observed the same changes in frogs and cattle with spinal defects inhabiting the areas where chemicals were used.

“If it's possible to reproduce this in a laboratory, surely what is happening in the field is much worse," Carrasco said. "And if it's much worse, and we suspect that it is, what we have to do is put this under a magnifying glass.”

Argentina adopted Monsanto farming methods 17 years ago, buying into the GMO market to help boost its flagging economy. Judy Hatcher, chairwoman of Pesticide Action Network International, told AP that given the increase in health problems in the areas where the products are used and lack of regulation, Monsanto should do more to help.

"As we've also learned in the United States, herbicide-resistant GE crops lead to dramatically increased pesticide use. And as weeds develop resistance to these chemicals, industry rolls out even more hazardous chemicals to battle the superweeds. Farmers get trapped on the pesticide treadmill."