Understanding what people believe the causes of autism to be has implications for experiences of familial guilt and stigma. Using a qualitative approach, we investigated how Brazilian healthcare professionals, parents of young and adult autistic people and young and adult autistic people consider the origins of autism and the interaction between the biological and social environment concerning the challenges autistic people encounter. Eight health professionals who assist autistic people, five young autistic people, six family members of young autistic people, five autistic adults, and four parents of autistic adults participated in the research. After analysis, two major coding themes emerged from the interviews: (T1) Perceived origins of autism: genetic, environmental, or both, (T2) The impact of the structured family environment. Our respondents consider autism in Brazil strongly related to genetic origins and little to environmental and social origins. At the same time, the context of the structured social and family environment can influence challenges and opportunities for autistic people.