Abstract

Contemporary philosophical discussion on human embryonic stem cell research has focused primarily on the metaphysical and meta-ethical issues suchresearch raises. Though these discussions are interesting, largely ignored are arguments rooted in the secular research ethics tradition already informing humansubject research. This tradition countenances the notion of vulnerability and that vulnerable human subjects (of which human embryos are likely members)ought to be protected from research-related harms. This is the basic idea behind the argument from vulnerability, and it enjoys prima facie plausibility. This articlepresents the vulnerability argument and then focuses critically on several lines of attack including: (1) twinning and totipotency arguments, (2) embryo-rescuearguments, and (3) natural loss arguments. The article concludes that there is no good defeater for the vulnerability argument, and, therefore, we have undefeated reasons for protecting human embryos from research related harms.