  If almost any status-enhancing research would be unethical, then it is important to know what kinds of transplants could enhance an animal’s moral status. Progress on this question can be made by asking why normal adult humans possess their comparatively high moral status.  On cognitive capacity views of moral status, an individual’s cognitive capacities give them their moral status, and the high-level cognitive capacities that normal human adults have is what gives them their relatively high moral status (VanDeVeer 1979). Given that high-level cognitive capacities are intimately related to the individual’s brain, this view obviously justifies focusing on transplants that could affect the brain in a way that enhances cognitive capacities. However, there are many constraints on the ability of human stem cells to significantly enhance an animal’s cognitive capacities. In some cases, the subject will be terminated before the development of the relevant cognitive capacities, thus side-stepping the entire problem. In many cases, cognitive enhancements would likely be prevented by the animal’s smaller skull size and shorter gestation period, as well as by the surrounding non-human cellular environment that would provide developmental cues to transplanted cells (Karpowicz et al. 2005, 124–126). In 2015, the National Institutes of Health hosted a workshop on research with animals containing human cells. Janet Rossant, chair of the workshop and a leading figure in chimera research, summarized several of presentations from current researches as follows: