Brazil has passed a landmark biosafety law that will legalize human embryonic stem-cell research, and may open the way for the cultivation of genetically modified crops.

The move ends a period of uncertainty and frustration for Brazilian cell biologists by allowing them to use stem cells from frozen embryos left over from in vitro fertilization. It also establishes a clear process for the approval of genetically modified crops.

Although the law was vigorously opposed by church groups in Brazil, it was passed by the lower house of Congress on 2 March and is expected to be signed into law by President Luiz Inácio Lula da Silva in the next few weeks.

Brazilian stem-cell researchers welcomed the law — even though it forbids the cloning of stem cells for therapeutic use. “We are so happy,” says Lygia Pereira, a cell biologist at the University of São Paulo.

A year ago, a preliminary version of the law passed by the lower house in Congress blocked the use of embryonic stem cells for research. But scientists and patient groups fought back to win the support of the Senate last October, and then that of the lower house this month.

“It is a huge step forward from the first draft that prohibited any kind of research with human embryos,” says Pereira.

Previous biosafety regulations hadn't covered the use of stem cells, focusing instead on transgenic crops, banning their planting and commercialization. But genetically modified seed is being smuggled into Brazil, and the new law may allow for the crops' official approval.

Under the law, a body called the National Technical Commission on Biosafety (CTNBio) will advise on whether a genetically modified crop can be planted and commercialized. A council of government ministers will then have the final say.

Leila Oda, president of the National Biosafety Association, says that the law will facilitate research in agricultural biotechnology in Brazil. “Anyone wanting to do research simply applies to CTNBio,” she says.