In the West, boomers' childhoods in the 1950s and 1960s saw significant reforms in education, both as part of the ideological confrontation that was the Cold War, and as a continuation of the interwar period. In the 1960s and 1970s, as this relatively large number of young people entered their teens and young adulthood—the oldest turned 18 in 1964—they, and those around them, created a very specific rhetoric around their cohort and the social movements brought about by their size in numbers, such as the counterculture of the 1960s and its backlash. In many countries, this period was one of deep political instability due to the postwar youth bulge; in China, boomers lived through the Cultural Revolution and were subject to the one-child policy as adults. These social changes and rhetoric had an important impact in the perceptions of the boomers, as well as society's increasingly common tendency to define the world in terms of generations, which was a relatively new phenomenon. That this group reached puberty and maximum height earlier than previous generations added to the tension between the generations.