Amy Gutmann tells The Scientist that the US presidential commission on bioethics looked for the "Aristotelian mean" between a no-holds-barred approach to synthetic biology and one that prevents the field from moving forward until all risk is removed. "We're likely to recommend that new organisms when they're created should be marked or branded in some manner to be able to monitor development in synthetic biology," Gutmann says, adding that there are multiple ways of doing so.