In January this year, two US agencies proposed the first substantial overhaul in 30 years of how they regulate genetically altered crops and livestock. Some plant scientists expressed relief. Some animal researchers used more colourful language.

The proposals — one to govern plants, the other to govern animals — came to wildly different conclusions. The US Department of Agriculture (USDA) suggests that many plants whose genomes have been altered by a single DNA letter change should not need approval before being released in the field. However, the US Food and Drug Administration (FDA) contends that animals whose genomes have been similarly changed might have to go through a rigorous evaluation before being released onto the market.