The author casts a broad net but purposefully so. It is one thread in the fabric of a society, and it is intertwined with others. Ethical concepts are tied to a society's customs, manners, traditions, institutions all of the concepts that structure and inform the ways that a member of that society deals with the world. The predominant moral theory in bioethics some say it isn't a theory at all is principlism. Principlism's critics have offered up a number of constructive alternatives.
Casuistry holds that moral decisions are made analogically, by appeal to paradigmatic cases.
Virtue theory focuses on the characteristics of the moral agent herself, as well as the goodness of the actions performed. Feminism illuminates the systematic oppression of groups by hierarchical social structures. Choosing among theories requires a set of criteria by which one would make the choice. Such criteria, though, either presuppose a metatheory of ethics or do not exist. Equally problematic is the gulf between theory and intuition.