Final answer:
The primary causes of ASD are not fully understood, but genetics may play a role, alongside issues with brain connectivity.
Step-by-step explanation:
Causes of autism spectrum disorder (ASD) remain largely unknown, with only a few forms such as Fragile X and Rett's Syndrome being clearly linked to genetics. Research indicates that variations in multiple genes may contribute to ASD, suggesting that it could require numerous mutations for the disorder to manifest. Moreover, ASD is thought to involve atypical neural connectivity, causing an aberrant level of synaptic pruning in some affected individuals' brains.
In the 1990s, a now retracted study falsely linked ASD to vaccines, promoting a damaging myth. Comprehensive follow-up studies have refuted this claim, showing there is no connection between vaccines and autism. Despite this, the misconception persists and has contributed to dangerous public health decisions, such as parents not vaccinating their children against preventable diseases.
Correlation does not signify causation; this is particularly relevant in the ongoing discussion about autism. The increase in autism diagnoses coinciding with more childhood vaccinations doesn't prove a causal link, especially considering the myriad of environmental and social factors that have also changed over time.