Genetic mutation, environmental factors like radiation, chemicals, drugs, pollution, smoking, parental age, and more.
Don't believe those autism pride groups that claim it is 100% genetic and has existed in its current form unchanged, from no mutation since the beginning of time. There are 60 mutations on average for each human being born and there are more than ever uncontrolled environmental factors we can't keep track of.
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I want to apologize to the entire forum. I have been a terrible person, very harsh and critical.
I still hold many of my views, but I will tone down my anger and stop being so bigoted and judgmental. I can't possibly know how you see things and will stop thinking I know everything you all think.
-Johnnyh