Legal challenge to Brazil's embryonic stem cell law

Brazil's attorney-general, Claudio Fonteles, has started a legal challenge to sections of the country's biosecurity law that he considers unconstitutional. The four-month-old law legalised research using human embryonic stem cells and set up a system for the approval of genetically modified crops.

Fonteles argued that the use of embryonic stem cells is unconstitutional because the Brazilian constitution protects the right to life. The debate hinges on the definition of when human life begins. The World Health Organization, and the Brazilian health ministry, says that life does not begin until an embryo attaches itself to the womb. Fonteles, however, believes that life begins after fertilisation, and has submitted supporting statements made in the past by nine scientists who agree.

Health minister Humberto Costa called the challenge a 'backwards step' that would deprive Brazilian researchers of the opportunity to cure a wide range of diseases. He insists that the law cannot be unconstitutional because the constitution only applies to the rights of people who have already been born.

The case has been referred to the Brazilian Supreme Court.