Response to the ISSCR guidelines on human-animal chimera research.

The International Society for Stem Cell Research (ISSCR) has recently released the 2021 update of its guidelines. The update includes detailed new recommendations on human-animal chimera research. This paper argues that the ISSCR recommendations fail to address the core ethical concerns raised by neurological chimeras-namely, concerns about moral status. In minimising moral status concerns, the ISSCR both breaks rank with other major reports on human-animal chimera research and rely on controversial claims about the grounds of moral status that many people will rightly reject. A more robust framework for regulating human-animal chimera research still needs to be developed.