There is no single smoking guy, but there are sure a lot of factors that are probable candidates behind the surge in Autism. From Dr. Joseph Mercola at theburningplatform.com:

Story at-a-glance
- Data suggest that 1 in 30, or 3.49%, of children ages 3 to 17 were diagnosed with autism spectrum disorder (ASD) in 2020
- The rate of autism in lower-income families is higher than in higher-income families, and lower-income families tend to have higher vaccination rates than higher-income families
- In 2010, the federal vaccine court conceded that Hannah Poling’s autism was the result of vaccinations, which “significantly aggravated an underlying mitochondrial disorder”
- Exposure to glyphosate, mercury, lead, aluminum and other chemicals, including phthalates and air pollution, is also implicated in autism
- Even acetaminophen, brand name Tylenol, use during pregnancy increases the risk of autism in children