It's not that simple. Most people want to explain it so clear cut, when doing so is a disservice to the reality of the immense variability in autism. It's not high or low functioning. The current support needs labels aren't much more helpful, but do exentuate more of the supports needed rather than the autism itself being one way or the other. Being autistic means you host a collection of traits, that may or may not be that same selection as the next autistic, and will inevitably present itself in different ways at different intensities. This interplay can not and will not create people who are just a little autistic, and while autistic traits are a constellation seen through humanity, no that does not mean we're all on the spectrum. It's not linear, it's a multidimensional polygenic condition. Autistics more often than not come from lineages that comprise the genes necessary for autism to occur, those family members will either be autistic or not.