This article illuminates a tension internal to Elizabeth Grosz's provocative theory of the irreducibility of sexual difference: while it establishes sexual difference as an ontological force of differentiation, it simultaneously delimits the forms sexual difference can take as fixed and uncrossable. This model thus privileges cissexual difference while invalidating trans modes of embodiment and identification, a move that perpetuates antitrans logic and practices while impoverishing feminist conceptions of the generativity of sexual difference. This article examines the uses of transsexuality throughout (...) Grosz's work on sexual difference, evaluating her claim that sexual difference is irreducible alongside her insistence that transsexuality is an impossible attempt to assume a bodily sex other than that assigned at birth. Illustrating how Grosz's account narrows the generativity of sexual difference down to unchangeable dimorphic sex, this article argues that fixed dimorphic sex is not simply irreducibly given but is the effect of normative schemas. If the power of sexual difference lies in its capacity to generate difference, it need not be constrained to an immobile binary of sexually specific bodies whose morphological possibilities are fixed. This article thus argues for the capacity of sexual difference itself to become otherwise than solely cisgender. (shrink)