[Zenst]

Aspie here, my parents mid 20's when I was conceived and I was a week late being born.

Would in retrospect say my farther was also somewhat upon the spectrum, so genetics are a factor. If those genetics can be activated or induced by other factors, I can not say though like all DNA we have which is dormant in some and not in others, external factors can come into play by that stress, chemical (environmental or self induced exposure) and other factors we are still learning about. Heck recently identified an organ in the humanbody that we had overlooked for all this time ( http://www.independent.co.uk/news/science/new-organ-mesenter... )

So who knows. All we do know is once a trait becomes the predominant trait in humanity then that is classed the new normal.