Researchers trying to find a better way of replacing dopamine in the brains of patients with Parkinson's disease say they believe the use of transplanted embryonic cells might prove to be the answer. Encouraging research using embryonic stem cells in a mouse model of Parkinson's disease was presented recently at the annual meeting of the American Association for the Advancement of Science [San Francisco, US; February 2001]; however, such research has a long way to go yet, as it is plagued by ethical and cultural issues.