Genetically modified crops reached 9 percent of global primary crop production in 2007, bringing the total GM land area up to 114.3 million hectares, according to Worldwatch Institute estimates published in the latest Vital Signs Update

The United States continues to be the global leader in production, accounting for half of all GM crop area

GM production has been on the rise since the crops were first introduced more than a decade ago, and it now includes 23 countries

But controversy over the benefits of genetic modification continues, including questions about the technology’s ability to deliver on promises of enhanced yields and nutrition.

a new scientific study funded by the Austrian government suggests that a popular variety of GM corn reduces fertility in mice, raising questions about the technology’s safety.

There are still many unanswered questions about GM crops