When advantages disappear: Long-term trends in gender and social origin inequalities and the rise of horizontal stratification in higher education in South Korea

Recent research on educational stratification has shifted focus from vertical to horizontal inequalities and the intersectionality of gender and social origin. Yet, little empirical research has examined how these multidimensional inequalities emerge and evolve over time. We argue that as traditional advantages by gender and SES decline, new horizontal inequalities may arise, maintaining advantage for privileged groups. Using nine nationally representative survey samples, we analyze South Korea, where higher education expanded rapidly in the late 20th century, examining cohort trends in gender and SES gaps across both vertical (college completion) and horizontal (institutional selectivity and STEM choice) dimensions. Our findings show that while the male advantage disappeared and SES disparities in college access narrowed, a new gap emerged, favoring high-SES males in STEM fields at selective universities. We also find suggestive evidence that rising labor market demand for STEM skills may be a factor explaining recent differences in major choice between high-SES men and women. This study reveals a new pathway of educational stratification shaped interactively by gender and SES.