Dr. Timothy Johnson (M.D., M.P.H.) is the medical editor for ABC News and has reported on health care issues for Good Morning America since 1975. He also provides on-air analysis of medical news for World News Tonight, Nightline and 20/20. Johnson holds joint positions in medicine at Harvard University and Massachusetts General Hospital in Boston. He is the founding editor of the Harvard Medical School Health Letter and coeditor of the Harvard Medical School Health Letter Book. He is the author of Dr. Timothy Johnson's On Call Guide to Men's Health, as well as coauthor (with former U.S. Surgeon General Dr. C. Everett Koop) of Let's Talk. Johnson lives in the Boston area. Having completed seminary before attending medical school, he serves as assisting minister of the Community Covenant Church in West Peabody, Massachusetts.