This chapter reports on two of our studies that have attempted to engage with the real-versus-artefactual debate, the first an unusual study that identified a range of candidate risk factors from 100 pieces of unprompted correspondence that were sent to an epidemiologist. The expertise of the correspondents qualified them as ‘lay epidemiologists’ as their expertise drew from their everyday knowledge of autism in the context of their family and working lives. These lay epidemiologists identified three broad categories of risk: medical technologies and practices, environmental pollutants and lifestyle factors. Second, the chapter gives an account of an epidemiological study we conducted that attempted to establish whether the growth in rates of diagnosis in children with autism over a ten-year period was mirrored by a parallel increase in the number of children with mild or severe traits of autism, and contextualises our findings. Finally, the chapter covers the idea of risk as a form of discourse in the light of Covid-19.