considering marriage statistics, my parents are hard to pinpoint as late/early marriers, considering my mum was 36 and my dad was 27 at the time they got married... That was a little more than 20 years ago and they still live happily together.
As for the spectrum, it seems that it has skipped a generation, and I theorize it comes from my father's side of the family considering the things my paternal grandmother has told me of my grandfather (my dad was too young to remember him as they seperated when he was quite young), and considering some of the things that hints some traits... My father shows some very subtle traits (such as becoming very absorbed in work), but not enough to be considered as autistic in any way...
Considering what my dad told me about his childhood, he had a few problems in school at first, like having problems sitting still and trouble at gaining friends at first could hint at some (very) mild AS, that he has since then, more or less bypassed as I have myself during my youth...