In the U.S., the development of extensive regulations for the protection of human subjects of research began in the 1960s and continued through the 1970s. The substance of these regulations reflects the American social and political climate of the time. There is a focus on rights--e.g., to be left alone, to be self-determining--reflected in elaborate requirements to assure the validity and documentation of informed consent. There is also a focus on systems of disinterested review and monitoring procedures to assure uniform adherence to the requirements of the regulations. To the extent that the U.S. has developed extensive regulations in this field, it may be viewed as more advanced than the U.K. And yet, it is apparent that there remain on both sides of the Atlantic very difficult and similar problems regarding the definition of responsible research. Such problems are illustrated by consideration of current controversies about the ethical justification of RCTs. There are some features of the U.S. regulatory system that I can commend to the attention of other nations as they develop policies for the protection of human research subjects. For example, a uniform requirement for informed consent and committee review appears to be responsive to some problems currently encountered in the conduct of RCTs in the U.K. A note of caution is in order, however. Some features of our regulatory policy and practices are excessively inflexible, wasteful of human resources, and occasionally counterproductive.