what are the generation categories
The literature defines four to five living generations (the names given may vary between authors). Also the description of the personalities of each generation may vary depending on the source. But overall the definitions are comparable. Some authors include cusper generations.
A familial generation is a group of living beings constituting a single step in the line of descent from an ancestor. In developed nations the average familial generation length is in the high 20s and has even reached 30 years in some nations.
Nobody likes to be labeled. We especially hated labels back in high school, when we were forced into one of several groups: jocks, nerds, theater kids, freaks and so on. Now imagine categorizing people based on the years they were born: the GI generation, Generation X, baby boomers, millennials.
In a 1993 Advertising Age editorial, the term Generation Y was used to describe what is now known as the millennial generation. But by 2005, it became clear that Ad Age's analysis of Gen Y was completely misguided.