The possibility of human/nonhuman acute neurological chimeras stirs much controversy. There is concern that neurologically humanizing a research animal could grant it protected moral status, making the performance of invasive experiments on the resulting chimera unethical. However, the real ethical problems may involve smaller increases in moral status along what may be termed the "moral staircase" of research subjects, both animal and human. Through appropriate recognition of incremental increases in moral status along the moral staircase, acute neurological chimera experiments may be permitted to ethically proceed. The real ethical issues around human/nonhuman acute neurological chimeras lie in the realm of animal welfare.
Keywords: Animal welfare; Humanization; Moral status; Neurological chimeras.