Not all medical trials contain an element of risk, But where regulatory oversight exists to safeguard the treatment of research subjects, and where drug companies and testing clinics can be held liable for injuries which may occur, they are very careful to keep all risks to an absolute minimum. It is true that until the late 1970s, taking part in such trials contained larger risk because researchers were not obligated to provide accurate information about the drug being administered. In addition, the subject population consisted mainly of prisoners who took part in trials in order to gain early release, and conscientious objectors in the military who wanted to avoid combat duty. As such, participation in trials was motivated by coercion, and thus subjects were not necessarily “volunteering” of their own free will. In the late 1970s and the 1980s, research involving human subjects in most developed nations came under scrutiny. Protective legislation was enacted as a result, and ethical guidelines were established to ensure the professional conduct of researchers. Subjects began to be recruited from the general population and to be paid for their services.