Gutter years of which century?

Halo: "Amber, like most of the postindustrialists aboard the orphanage ship Ernst Sanger, is in her early teens.... Their parents, born in the gutter years of the twenty-first century, grew up with white elephant shuttles and a space station that just went round and round, and computers that went beep when you pushed their buttons."

The Halo chapter takes place in "the fourth decade" or 2030s, probably early in that decade given that (in Tourist) Amber was "about 160 million seconds old" on "the eve of the third decade" (i.e., just before 2020). Isn't it at least as likely that the parents would have been born in the 1990s - the gutter years of the twentieth century?