The media decided what millennial culture and values would be decades ago, before some of us were even born. William Strauss and Neil Howe, a popular-historian duo, coined the term “millennial” in 1987, to refer to the children who would graduate high school in the year 2000. And in their book Millennials Rising, published in 2000, they saw fit to describe the character of this newborn generation.
Source: The Myth of the Millennial as Cultural Rebel | New Republic