In the arena of gender transitioning, the status of the letter has become paramount. Following the multiple meanings of the signifier “letter,” it becomes apparent that to obtain the “right” to a letter (M/F), which would replace the one from which one feels estranged, one needs to request a letter so that an hormonal intervention —e.g. hormone blockers in young children— is granted. In this paper, I turn to recent debates about the use of hormone blockers in transgender children in order map out a myriad anxieties concerning our understanding of the child's process of coming into his/her gendered self. I ask what is it that the debate cannot metabolize when it addresses questions about the child's agency, autonomy, and future, about the relation between nature and socialization, and particularly, about what is conceived as naturally occurring versus what medically induced in the transitioning body. I argue that the debate is caught in the very same anxieties that accompany the process of transitioning and that the transitioning subject's worry over “arriving into gender” as well as her wish to become fully readable to the other are both mirrored in the debate. I suggest instead that we approach the hormones request as a kind of relay, as a letter in process, whose destination, arrival, and accurate reading one cannot guarantee.