The answer is Millennials.
Millennials, also known as Generation Y, are generally considered to be those born between 1981 and 1996. This generation was in their formative years or early adulthood during the events of September 11, 2001. The impact of 9/11 on Millennials was significant as it shaped their worldview, influenced their political and social attitudes, and affected their sense of security. Many Millennials were old enough to remember the events clearly and were directly affected by the subsequent changes in global politics, security measures, and economic conditions.
Generation X, typically defined as those born between 1965 and 1980, were already adults at the time of the September 11 attacks. While they were certainly affected by the events, they were not in their formative years, which is a critical period for shaping generational identity. Therefore, the impact on Gen X is considered less profound in terms of generational influence compared to Millennials.
Generation Z, often defined as those born from the late 1990s to the early 2010s, were either very young or not yet born during the events of September 11, 2001. As a result, they did not experience the events directly and are more influenced by the post-9/11 world rather than the events themselves.
Baby Boomers, born between 1946 and 1964, were well into adulthood by the time of the September 11 attacks. While they experienced the events and their aftermath, the impact on their generational identity is less significant compared to Millennials, who were in a more impressionable stage of life.