This chapter presents a discussion on bioethical casuistry, demonstrating it in practice with two cases of animal biotechnology. It recommends the use of bioethical casuistry as the most useful method of moral evaluation. It analyzes two contrasting projects with human-medical implications: the “biopharming” of transgenic goats in order to harvest proteins in the animals’ milk; and the creation of genetically modified pigs for the long-term goal of xenotransplantation. This chapter shows that the construction of a continuum of moral permissibility for the area of animal biotechnology provides a way to evaluate individual projects in transgenic science or animal cloning.