  Most groups that have issued an opinion on chimeras acknowledge the existence of traditional animal ethics issues, but are content to assert without argument that the use of non-human animals in chimeric research is justified because of its scientific and, ultimately, clinical importance. On the one hand, this attitude seriously underestimates the difficulties, abundantly articulated in the animal ethics literature, of justifying the use of non-human animals along these lines without either (a) implying false and morally odious conclusions about research on cognitively disabled humans or (b) taking an uncharitable view of the cognitive capacities of non-human animals that is inconsistent with current research on animal psychology. On the other hand, this attitude probably reflects a realistic assessment of the limited willingness of these groups’ audiences (primarily scientists and research oversight bodies) to seriously consider the possibility that most animal research is ethically unjustifiable. The earliest evaluation of chimeras in terms of traditional animal ethics considerations is by David DeGrazia, who has argued that the psychological characteristics of great apes (chimpanzees, bonobos, gorillas, and orangutans) makes them “borderline persons.” Borderline persons have full, or near-full moral status, which makes it unethical to use borderline persons in what DeGrazia calls “neural chimeric research,” research intended to lead to the growth of human neurons in the subjects’ brains (DeGrazia 2007, 325).