Biotechnology and sustainable agriculture are complimentary, says Pamela Ronald, professor of plant pathology at the University of California, Davis: "The number of people on Earth is expected to increase from the current 6.7 billion to 9 billion by 2050. How will we feed them? Genetically engineered crops will play an important role." Her opponent in the debate is Charles Benbrook, chief scientist at the Organic Center: "Biotechnology is not a system of farming. It reflects no specific philosophy nor is it guided by a set of principles or performance criteria. It is a bag of tools than can be used for good or evil, and lots in between," he says.