What is gene-edited food?
For many years, farmers produced new varieties through traditional cross-breeding techniques.
They might, for instance, combine a big but not very tasty cabbage with a small but delicious one to create the perfect vegetable.
But this process can take years, because getting the hundreds of thousands of genes in cabbages to mix in just the right way to produce large but tasty offspring is a matter of trial and error.
Genetic methods remove the random element.
They let scientists identify which genes determine size and flavour, and insert them in the right places to develop the new variety much more quickly.
Which genetic techniques are used?
Genetic modification (GM), which has been common in most parts of the world for more than 20 years, though not in the European Union (EU).
GM involves adding genes to a plant's DNA from a different species of plant - or even an animal. It creates new varieties which could not have been produced through cross-breeding.
Cisgenesis, which is like GM, but involves adding genes from the same or very closely-related species, which the new rules will allow if the resulting crop is something that could have been produced through traditional cross breeding.
Gene-editing (GE), which is a much newer technique that lets scientists target specific genes. The new law lets plant breeders switch them on or off by removing a small section of DNA - again, provided the resulting crop could have been naturally produced.
Are gene-edited foods safe?
Scientists insist that each of the three genetic techniques produces food that is safe to eat, and point out that all food is rigorously tested.
They argue that GM crops have been consumed by billions of consumers in North and South America and Asia for more than 25 years with no ill-effects.
However, concerns over health risks and the environmental impact have meant that neither GM nor GE crops can be commercially produced or sold in the EU, although there are some signs that this may change.