Brazil’s Supreme Court ruled Thursday that scientists can conduct embryonic stem cell research, which holds the promise of curing Parkinson’s disease and diabetes but raises ethical concerns about the limits on human life.

Six of the court’s 11 justices upheld a 2005 law allowing embryonic stem cell research and turned down a petition filed that same year by then-Attorney General Claudio Fontelles, who argued the law was unconstitutional because it violates the right to life.