Autism Spectrum Disorder

While the prevalence of autism continues to increase, its cause remains unknown.


At this point, the cause of autism remains unknown. However, one theory that has strong scientific evidence is that genetics play a significant role in contributing to the occurrence of ASD. Studies show the concordance rate for identical twins is much higher than for fraternal twins, and ongoing research is beginning to identify genes that may put an individual at risk.

Additionally, in the last decade, we have seen considerable speculation about environmental toxins, diets, and vaccines, but there is no convincing scientific evidence that demonstrates a causal link to ASD. In particular, there is overwhelming evidence that vaccines do not cause ASD. As a result, adherence to these speculative beliefs is tragic because children are harmed by not receiving life-saving vaccination.

Finding the answer will require long-term, painstaking, rigorous, and sophisticated scientific investigation. Professional responsibility and ethics demand that care be taken not to over-speculate, misrepresent nor present mere hypotheses as facts for the causes of autism.

  • As of December 2021, about 1 in 44 children has been identified with autism spectrum disorder (ASD) according to estimates from CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network, which is 50 percent higher than previous estimates reported in 2012 of 1 in 88 children
    (Center for Diseases Prevention and Control, CDC 2014)
  • 1,100,000 cases of autism in China; 650,000 in the UK; 500,000 in the Philippines; and 180,000 in Thailand
    (the World Health Organization, WHO, 2009)
  • 49 children in every 10,000 is diagnosed with the disorder in Hong Kong
    (epidemiological study by V. Wong & S. Hui (2007) of The University of Hong Kong)
  • ASD is more than 4 times more common among boys than among girls.
    (Centers for Disease Control and Prevention, CDC, ASD)  Read article
  • Studies in Asia, Europe, and North mAmerica have identified individuals with ASD with an average prevalence of about 1%. A study in South Korea reported a prevalence of 2.6%.
    (Centers for Disease Control and Prevention, CDC, ASD)
  • Approximately 67 million people worldwide are affected by autism.