The problem is that society has deceptively labelled a large range of diagnoses
as autism, where in fact there many different forms of autism.
Some of you might have noticed that I underlined the word diagnoses. Autism is generally NOT any Bone-fied illness, and in the cases it is, is very much magnified by the effects of society.
Downs Syndrome is most probably genetic, as reported in various studies. I have NOT, however, analysed these findings, and therefore there is no current Truth-based perspective to these findings.
Aspergers Syndrome is, however, largely caused by child abuse, child neglect, and emotionally distant and uncaring mothers. I have personally investigated AS for some time, and have lived near a community programme for same. AS is a Forbidden Truth matter, because of the child-abuse and societal-poison-container-allocation aspects of it. This is so wether or not it is the sole cause of AS. I have been able to determine that :
1. Most of the effects on personality are simply due to child abuse, ostrisization, distant and abusive mothers, and so on.
2. There may be other factors at play, but these are minimal. The real meaty part of the diagnosed behaviours and personality traits are due to negative experiances in the True Reality.
3. That there is no actual basis for these catagories and diagnoses i.e. no genetic data, no blood test, no life-long studies that are made on subjects and so on.
The OP suggests racial "interbreeding" causes. That makes no sense, because there is no known genetic component to most forms of autism. I suppose you would have rejected any link between increased levels of credit-card spending and autism, because it is obviously ridiculous. There being two trends at once in no way proves anything.