I wonder about diet especially in the early years. ww2 generation did not eat much crappy food in their lives and silent generation maybe some. Boomers in their adult lives and Xers in high school. Millenials from early on. Im not saying this is 100% all across the board but it feels right to me from a typical person standpoint. It often seems like a lot of bad things are way worse when you are exposed to them when developing.