In the United States, interest in bioethics increased significantly during the 1970s, as new technologies and changing social mores combined to focus attention on contentious issues in medical research and treatment. New legal developments, both statutory and case based, also began to address reproductive freedom, informed consent to research and treatment, organ transplantation, end of life issues, and other matters. Since the 1970s, the law has relied on ethical principles such as autonomy and respect for persons; bioethics has relied on the law to implement and institutionalize bioethical concerns into the nation's social fabric.