I think what is needed is to understand what factors (e.g. environmental, genetic, etc) lead to autism so we as a society and parents can try to prevent it.
although you may have read in some headlines that autism is 'on the rise' and there are an increasing number of diagnoses, I think this is a misinterpretation.
statistics looks like it's on the rise because 50 years ago we didn't know what autism was, and instead we gave diagnosis like 'idiot' and 'imbecile'.
I don't think it's a stretch to say society has always had autists, maybe rather than trying to understand why autism happens energy would be better spent in trying to understand autistic individuals.
Autism is a disease, widespread access to screening and more information is not "eugenics"... you're equating disease prevention with forced government sterilization and selective breeding.