A science education center at a university medical school had grant funding to develop a genetics curriculum unit, but needed a dissemination plan. A statewide science teacher organization that provided professional development training was facing decreased funding. These two groups combined their efforts, and created a unique partnership, called BEGIN (Biotechnology, Ethics and Genetics Instructional Network) that has brought together university medical and science faculty and high school biology teachers. The main goal of this partnership is to provide high school biology teachers with new instructional tools to face the challenges of teaching genetics and bioethics in a manner that is content-rich, research and standards-based, and relevant to students' lives. This article describes the BEGIN partnership and summarizes the tiered approach used for designing, pilot-testing, and disseminating a new problem-based learning (PBL) curriculum module on the bioethics of DNA testing for Huntington's disease. The article also provides some preliminary data on the effectiveness of this approach in transforming teacher practice. (Contains 2 figures.)