I wonder how they decide these things. I guess it's unmistakeable that the Baby Boom began around 1945, but where's the other end come from?
The Baby Bust. In 1965 the birth rates collapsed which is where the Xers start and which is why Gen-X is often referred to as the Baby Busters
The Birth rates picked up again in 1976 so it's often used as the start of Gen-Y or the Echo Boom. Though often 1982 is the start because the milestone year 2000 would have been the year they graduated High school hence their name Millennials.