In terms of their understanding of the causes of autism, mainstream researchers and biomedical activists appear to occupy parallel universes. Over the past 30 years, scientific study has focused on genetics and attempts to discover the neurobiological pathways leading from defective genes to the distinctive behavioural features of autism. Authorities – such as Patrick Bolton in the UK and Jeremy Veenstra-Vanderweele in the USA – reckon that genetic factors account for 90 per cent of cases of autism, a rate higher than for most other genetically influenced conditions, whether in medicine (diabetes, coronary heart disease) or psychiatry (schizophrenia, bipolar affective disorder). Yet for anti-vaccine parent campaigners like Laura Bono, genetic research is a distraction of energy and a misdirection of resources from the quest to discover environmental causes of autism. As we have seen, the belief of the biomedical movement in the notion of an ‘autism epidemic’ is crucial to the elevation of environmental over genetic factors (as the activists say, ‘whoever heard of a genetic epidemic?’). Though the rise of genetic theories in the 1970s may have helped to relieve an earlier generation of parents of the burden of

psychogenic ‘parent-blaming’ theories, for today’s biomedical parents genetic explanations imply not only an unwelcome degree of parental responsibility, but also fatalistic notions that autism is a constitutional, lifelong and immutable condition. Environmental theories by contrast, raise hopes of prevention, treatment, even cure.