Pah! I was a size 10 (still am), no sign of diabetes anywhere in the family tree & Dad was under 40 when both his kids were conceived.
Autism sadly seems to cut across all nationalities cultures/ethnicities with equal cruelty from my own anecdotal observations. Are they trying to say that minority parents find it harder to access the services that influence outcomes?
The diabetic link may tie in with some nutritional theories, but I think that alone it's very oversimplified.
I'm convinced the "autistic spectrum" is actually about 20 different conditions neuro science hasn't fully differentiated yet and the causes are just as vast ranging from environmental damage right through to plain old genetics. The spectrum and individual differences (especially in the sensory arena) just seem too vast for any other explanation.
There seems to be a general swing back to blaming parenting now that budgetry pressures are becoming more pressing on services due to the state of major Western economies.