Moral equivalence and the grounds of moral status in stem cell-derived embryo models: a response to de Graeff and De Proost

Gyngell <i>et al</i> argue that no intrinsic differences exist between embryos derived from fertilisation and stem cell-derived embryo models (SCEMs) that would justify attributing a higher moral status to the former. Nienke de Graeff and Lien De Proost challenge this claim by emphasising the diversity of SCEMs and by broadening moral evaluation beyond direct moral status to include relational, symbolic and instrumental value. This response argues that their pluralistic framework does not, in fact, undermine moral equivalence in cases where SCEMs successfully instantiate embryo-like human developmental organisation. Once the distinction between properties that ground moral status and considerations that merely shape social or regulatory responses is made explicit, no principled basis remains for differential moral standing. Variation among SCEMs defeats equivalence only where embryo-like organisation is absent; where it is present, moral parity follows. Likewise, relational and instrumental values may justify different governance strategies, but they cannot ground differences in moral worth without collapsing into policy convenience. Rejecting binary thinking does not require denying equivalence where morally relevant features coincide. Either SCEMs fail to model embryos, in which case equivalence never arises, or they succeed and must be treated as morally equivalent in respect of status. What cannot be coherently sustained is embryo-likeness without moral parity.