It is not just the English-speaking world. Most of Europe experienced a baby-boom in the years after WWII (Germany a decade later). This had very real social co

It is not just the English-speaking world. Most of Europe experienced a baby-boom in the years after WWII (Germany a decade later). This had very real social consequences, for example the impact of the youth culture in the late 60's. So at least the baby-boom generation is not an arbitrary distinction but a very real social phenomenon. That said, I think "milleanials", "gen-X" etc. are arbitrary divisions - just a shorthand for talking about a specific age group.