I am sure you have made a thorough job of researching the available statistics Iain. I suspect that at best the figures will give only a hint of the extent of autism, but as you say autism seems to affect varied cultures.  I am not knowledgeable in the field of statistics or autism, but I can’t accept that the figures would have taken into full account the extent of the problem of accurate diagnosis and the variables around criteria, gender, masking, educational background, culture, religion, economic situation, mental health …. etc. Moreover, existing studies seem to be small, or else aren’t accessible to the public. Where I live, parents of school age children are struggling to get their children assessed and some young people in the 18 - 25  age bracket are being referred only now. In this day and age, how have these young people gone through school and been missed or prevented from receiving a diagnosis. I have recently become interested in genomics and have learned that those of us not of African origin have between 1% and 3% genetic material derived from Neanderthals because Sapiens and Neanderthals interbred. The ancestors of today’s Asians interbred with Denisovan’s and those living in Papua New Guinea carry between 3.5% and 5% Denisovan genetic material. The Tibetans’ ability to live in extreme conditions at high altitudes is due to their Denisovan ancestors and the first Europeans were better able to cope with viruses such as the cold, and other pathogens, thanks to Neanderthal DNA. I cannot find any research looking at a possible connection between genetic origins and autism, but it is a fascinating and fast moving subject.

If you look at sub-Saharan Africa there is more genetic diversity and more relict DNA from other earlier human species.

I don't think ASC is confined to one genetic grouping, I think it's a basic human trait.

Have a look at Gina Rippon's book, The Gendered Brain, to get some idea of how small the samples used in many of these studies really is and the massive conclusions they come to from such a minute sample size.

I have looked up sub Sahara African genetic diversity now and I remember reading about the genetic admixture on the the BBC News App. It is interesting stuff and I get your point. I still wonder if there is a genetic component to autism as traits like personality are probably at least partially genetic. Aren’t psychologists still arguing over the nature versus debate? I thought I had read somewhere that an autistic person would be more likely to have at least one biological parent or child than a non autistic person and that it has a genetic component? Is it not likely that autism has been inherited through the admixture of one or more types of hominin, in the same way that there is a genetic component to hair colour or eye colour? Are sub Saharan’Africans more or less likely to be autistic than people in other parts of the world?  The idea of autistic people being just as we should be, processing information in different ways, is how I think of myself, even though I can get overwhelmed and struggle in a neurotypical world. So far, I have read Tom Higham’s “The World Before Us: …” and have just started “Human Peoples: on the Genetic Traces of Human Evolution, Migration and Adaptation” by Lluís Quintana-Murci. I am going to read Gina Rippon’s book next so thank you for the recommendation CatWoman. I hope I haven’t ranted too much about something I know next to nothing about, it is just me thinking aloud.

I have looked up sub Sahara African genetic diversity now and I remember reading about the genetic admixture on the the BBC News App. It is interesting stuff and I get your point. I still wonder if there is a genetic component to autism as traits like personality are probably at least partially genetic. Aren’t psychologists still arguing over the nature versus debate? I thought I had read somewhere that an autistic person would be more likely to have at least one biological parent or child than a non autistic person and that it has a genetic component? Is it not likely that autism has been inherited through the admixture of one or more types of hominin, in the same way that there is a genetic component to hair colour or eye colour? Are sub Saharan’Africans more or less likely to be autistic than people in other parts of the world?  The idea of autistic people being just as we should be, processing information in different ways, is how I think of myself, even though I can get overwhelmed and struggle in a neurotypical world. So far, I have read Tom Higham’s “The World Before Us: …” and have just started “Human Peoples: on the Genetic Traces of Human Evolution, Migration and Adaptation” by Lluís Quintana-Murci. I am going to read Gina Rippon’s book next so thank you for the recommendation CatWoman. I hope I haven’t ranted too much about something I know next to nothing about, it is just me thinking aloud.

Yes and the media likes to pick up and distort the facts around people who aren’t neurotypical or who have mental illness. Not everyone checks news source credentials. 

No you've not and thak you for telling me the books you've read, I want to read them too, when I've finished my book, I'm still doing the research for that.

There probably is a genetic component, but I doubt it's just one gene, but areas on multiple genes. I think some psychologist would like to think we arrive as a blank slate to be imprinted on by our upbringing and others think arrive with somethings already there, personally I think it's a bit of a pointless debate, like how many angels can dance on the head of a pin? It's almost certainly a mixture of both nature and nurture, I think some of the newer stuff on psychopaths show us that, some will become awful monsterous killers, others not and the only thing that makes sense is them being brought up in totally different environment, or at least according the the researchers. But then I suspect psychopathy is a spectrum too, so not everyones psychopathy will be the same anyway.