There is a huge debate in the medical community about those figures regarding autism. At least part and maybe all of the reason for the increase in autism has to do with two factors that are not the least environmental. Firstly, many newer, more mild forms of autism are known to exist today. These milder forms have always existed but they were not until recently counted as autism. Secondly, screening for autism has dramatically improved, thus increasing the numbers without actually increasing the real rates of autism. There also exist groups that do blame other environmental factors, but the factors are so numerous and varied that they are difficult to back up with firm, unbiased evidence that exists in sample sizes that are statistically significant. These environmental factors may be real, but proving them is extremely difficult. SI2305