You don't have to identify the root cause for that though, all it takes is studying the prevalence of a disease across family trees, that would be evidence of genetic expression.
You don't have to identify the root cause for that though, all it takes is studying the prevalence of a disease across family trees, that would be evidence of genetic expression.
Autism appears to be hereditary, but the eugenicists haven't identified a genetic component (nor have any other researchers, who are admittedly less motivated to find one). We're pretty sure that autism is a developmental condition, but the correlations with other things are… weird. (Off-hand: fœtal androgen and œstrogen levels, some chromosomal disorders, some mitochondrial disorders, a handful of rare single-point mutations, maternal autoantibodies, gut flora, something something oxidative stress (doesn't replicate, but keeps coming up).) Maybe they all tie into a "single cause" somehow, but… well, there's no single cause for eye colour (developmentally a much simpler trait), so the whole idea that autism is a deviation from the baseline, explicably attributable to a single factor, is somewhat of an article of faith.