Using Ian Hacking's notion of "making up people", this paper argues that human chimeras--people who contain more than one genetically distinct cell population--have been made up. As with multiple personality, the discourse surrounding the phenomenon of chimerism offers a novel vantage point for examining the socio-political processes of subject formation. Evidence from archives, interviews with cell scientists, and popular sources will show that, in a strange leap that has come to seem self-evident, journalists, laypeople, and even scientists have come to equate genomes with selves and hence conclude that chimeras are more than one person. Thus far, the challenge that chimeras pose to the simple alignment of genome-body-person has been limited both by relegating chimeras to freak show status and by liberal institutions' demands that individuals be singular.