title: Developing human-nonhuman chimeras in human stem cell research: ethical issues and boundaries.
abstract: The transplantation of adult human neural stem cells into prenatal non-humans offers an avenue for studying human neural cell development without direct use of human embryos. However, such experiments raise significant ethical concerns about mixing human and nonhuman materials in ways that could result in the development of human-nonhuman chimeras. This paper examines four arguments against such research, the moral taboo, species integrity, "unnaturalness," and human dignity arguments, and finds the last plausible. It argues that the transfer of human brain or retinal stem cells to nonhuman embryos would not result in the development of human-nonhuman chimeras that denigrate human dignity, provided such stem cells are dissociated. The article provides guidelines that set ethical boundaries for conducting such research that are consonant with the requirements of human dignity.
authors.affiliation: Institute of Medical Science, University of Toronto, Ontario, Canada.
authors.forename: Phillip
authors.initials: P
authors.lastname: Karpowicz
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Cohen
authors.forename: Derek
authors.initials: D
authors.lastname: van der Kooy
mesh_terms: D032761:Animal Experimentation; D000818:Animals; D001921:Brain / Q000166:cytology*; D002678:Chimera; D032981:Dehumanization; D033041:Embryo Research; D004644:Emotions; D026689:Ethical Analysis; D017408:Guidelines as Topic; D040821:Human Characteristics; D006801:Humans; D019368:Nature; D012160:Retina / Q000166:cytology; D013045:Species Specificity; D033581:Stem Cell Transplantation / Q000941:ethics* / Q000592:standards; D013609:Taboo