As everyone here knows the spans of a generation is not fully agreed upon by people. You'll come up with a span for a generation, but you'll also have those who come up with generation spans that are different than yours. For example I've seen tons of sources that show different span of years for generation Y (most tend to start in the 1980s and end in around 1995-1996 and some in 2000-2001).
Edit: Oops! Seems I messed up on the title of this thread. My bad.