Also consider the up-tick in dangerous or non-neurotypical conditions in the first world (i.e., US) versus the third world: lower fertility rate, peanut allergies (does ANYBODY over 30 remember not bringing peanut butter to school?), and Autism-spectrum reorders.
(Most importantly, ObB5:
Ambassador Londo Mollari: [wincing] You haven't changed.
Timov: You have. You've devolved.