The Bank of Korea published an issue note examining why labor force participation among men ages 25-34 fell from 89.9% in 2000 to 82.3% in 2025, with the decline among Millennial men persisting into their late 30s. The note attributes the trend to three main forces: intensified competition for higher-skilled jobs as highly educated women entered the labor market in greater numbers, industrial restructuring that reduced demand for less-educated men, and narrower entry routes for youth as older workers remain employed longer and AI adoption hits entry-level roles. Its cohort analysis finds the sharpest deterioration among highly educated men. For men born in 1991-95 with a college degree or higher, the probability of labor force participation was 15.7 percentage points lower than for the 1961-70 reference cohort, while the comparable figure for women rose by 10.1 percentage points. The note says this reflects a convergence in the gender mix of professionals and clerical workers, with women and men now present in roughly equal shares. For men with an associate degree or lower, the probability of participation in 2025 was 2.6 percentage points below 2000, which the note links to a decline in middle- and low-skill jobs in manufacturing and construction. It also points to crowding effects from aging and AI, noting that the elderly employment rate rose by 12.3 percentage points from 2004 to 2025, mainly in high-skill occupations, and that 98.3% of youth employment lost over the preceding four years was concentrated in sectors with higher AI exposure. The note argues that policy support should focus on smoother labor market entry for male youth through stronger technical education and broader labor market reform, rather than short-term youth support alone. It points in particular to easing rigid employment protection for regular workers and improving transitions from non-regular to regular employment.