Neurodiversity, the advocacy position that autism and related conditions are natural variants of human neurological outcomes that should be neither cured nor normalized, is based on the assertion that autistic people have unique neurological differences. Membership in this community as an autistic person largely results from clinical identification, or biocertification. However, there are many autistic individuals who diagnose themselves. This practice is contentious among autistic communities. Using data gathered from Wrong Planet, an online autism community forum, this article describes the (...) debate about self-diagnosis amongst autistic self-advocates and argues for the acceptance of the practice in light of the difficulties in verifying autism as a ‘natural kind.’ This practice can counteract discriminatory practices towards and within the autistic community and also work to verfiy autistic self-knowledge and self-expertise. This discussion also has important implications for other neurocommunities, neuroethical issues such as identity and privacy, and the emerging field of critical autism studies. (shrink)