Scientists are working on modifying cells in order that they might “turn specialized molecules into tiny, self-contained factories, creating cheap drugs, clean fuels, and new organisms to siphon carbon dioxide from the atmosphere”. One of the motivations is that synthetic “drugs factories” would by-pass natural sources of drugs i.e. plants which are vulnerable to environmental changes and suffer price fluctuations. Jay Keasling, professor of biochemical engineering at the University of California at Berkeley, is working on a way to replace the natural form of artemisinin, an effective antimalarial, with a synthetic version created by specially engineered cells. Inevitably, this throws up all kinds of ethical questions.