Zeneca does this by genetically engineering its maize to produce an enzyme, called ribonuclease, which interferes with pollen production.

ECONOMIST: Terminator genes

The Harvard team has exploited such dogged persistence by genetically engineering stem cells to make them produce a protein called cytosine deaminase.

ECONOMIST: Cancer treatment

Genetically engineering people in the way that Dr Baker engineered his mice is obviously out of the question for the foreseeable future.

ECONOMIST: A way to counteract part of the process of growing old

The agency treats genetically engineered products as though they pose some inherent, systematic, unique risks, when theoretical considerations, risk-assessment experiments and practical experience make it clear that they do not: A quarter-century-old scientific consensus holds that the molecular techniques of genetic engineering are an extension, or refinement, of less precise and predictable techniques for genetically improved products with which consumers and government regulators have long familiarity and comfort.

FORBES: The EPA's Lisa Jackson: The Worst Head of the Worst Regulatory Agency, Ever

As the world's largest producers of genetically modified crops, the US and Canada have a vested interest in downplaying the concerns about genetic engineering raised by environmental groups.

BBC: Fight on GM food labelling

Resistance to genetically modified foods, technical difficulties, legal and business obstacles and the ability to develop improved foods without genetic engineering have winnowed the pipeline.

FORBES: The Rationalist