What causes autism?

As an expert in the field of cryptocurrency and finance, I understand that my area of expertise does not directly relate to the medical condition of autism. However, I am always curious to learn more about complex topics, so let me ask you this: What are the current theories and research surrounding the causes of autism? Is it a genetic disorder, or is there an environmental factor that plays a role? Are there any lifestyle changes or interventions that have been shown to reduce the risk of developing autism? I'm eager to understand the scientific consensus on this important topic.