I'm older, and was taken into 'care.' I was also physically disabled and had a DIV education code. Then labelled as Spastic, and ESN.
So went down the 'unsuitable for fostering or adoption' route straight to the 'unmerciful sisters.' It was a good 50% full of kids who would nowadays be automatically considered autistic, just from the stimming, lack of eye contact, inability to deal with change, and meltdowns regardless of threats of violence, or into cold baths for hours if they did.
Then they were considered odd, brain damaged, aggressive, or suffering from 'infantile dementia' and trained (or not!) for menial work.
Later my DIV code and ESN diagnosis changed, and I became part of the 'everybody's dyslexic now' wave of diagnoses.
I'm officially NT, but fell for a a man who I now know is ND and so clearly are a lot of his family going back many generations. One got a formal diagnosis after being admitted to Broadmoor. Lots of uncollected awards for bravery. Uncollected because they were only doing their job, and officially un social bunnies.
ASD definitely runs in some families.
It all came out when Gt Ormond street took a look at our 'strange' spiky profile DC and said Aspergers, then asked to meet Dad, and Grandma had an absolute hissy fit about keeping 'family secrets.'
ND children were always there, just not diagnosed properly. There's an increase in recognition and diagnosis, an understanding that early intervention can lead to better adaptability, less autistic children are hidden away, and potentially more ND people procreating. There may be other factors as well.