Among Latin American countries, Brazil was an early adopter of embryonic stem cell research: in 2005 the nation's legislators approved a biosecurity law that included a section supporting the scientific use of such cells.

However, this early legal acceptance of stem cell research was quickly thrown into doubt. Soon after the approval of the biosecurity law, Brazil's attorney general at the time, Claudio Fonteles, decided to challenge the section allowing experiments with ESCs. Fonteles argued that the use of such cells went against an article in the country's constitution that guarantees the right to live.

Brazil now looks set to regain its reputation as a place where scientists can comfortably investigate embryonic stem cells. On 29 May the country's supreme court voted 6-5 in favor of upholding a 2005 law allowing this type of research. The ruling means that scientists there can continue using stem cells derived from donated embryos that have been frozen for more than three years or are unviable.

During the past three years, as the legal battle continued, few scientists decided to continue working with embryonic stem cells. In a country full of choices and short of money, many felt it was simply too risky to bet on a Supreme Court decision in support of ESC research.

For those that went ahead despite the legal uncertainties and pursued experiments involving embryonic stem cells, the final court decision has brought relief. “It was a great step,” says Lygia Pereira, a scientist from University of São Paulo who continued to develop embryonic stem cell lines during the dispute. Labs such as Pereira's are now expecting more applications from students and are seeking to establish partnerships with institutions overseas.

The Supreme Court's decision echoes the broad public support for stem cell research in Brazil. According to a survey released by Ibope, the nation's largest polling agency, 75% of Brazilians fully support the scientific use of embryonic stem cells.

In the same month that the recent Supreme Court decision became known, the government announced the creation of the Rede Nacional de Terapia Celular (the National Network of Cell Therapy), which will, among other things, help train new scientists in this field. As part of the new network, the government also granted 21 million Brazilian reais ($13 million) for two years of research with stem cells. “It is a new field of research with great scientific potential and it is affordable for the country, so it makes sense to Brazil to invest in it,” says Reinaldo Guimarães, the head of science, technology and strategic resources at Brazil's Health Ministry.

But there are still some obstacles in the way for scientists pursuing embryonic stem cell research in Brazil. The original biosecurity law approved three years ago stated that experiments could be done only with embryos frozen before March 2005, limiting scientists from using more recently derived cells. Researchers say they hope to see this restriction reconsidered soon. In the meantime, Brazil's National Health Surveillance Agency has announced that intends to eventually publish rules on the handling of embryos donated for research.