Daniel Callahan, an American philosopher and biomedical ethicist, discusses ethical questions that have arisen as a result of the rapid development of medical technology. Callahan co-founded the Hastings Center, an influential bioethics research institute in New York. He discusses several areas of medical development including world population growth, procreation, shaping human behavior, and control of human death. He contends that these are areas in which humans have newfound, but ultimately incomplete, power. How that power can or should be used is often unclear. Callahan argues that there may never be definitive answers, but that there will always be more ethical questions to pursue. The lecture is followed with questions from the audience. Recorded November 13, 1975 at The 92nd Street Y, New York.