Is single-sex education better than coeducational schooling?

What can single-sex schooling actually improve?

For girls, single-sex education appears to boost political and civic engagement. A large-scale natural experiment in South Korea found that women who attended all-female high schools were more likely to vote, join organizations, and pursue leadership roles later in life—effects that lasted for decades [2]. This suggests that removing boys from the classroom may free girls from certain social pressures or stereotypes that suppress their ambition.

For boys, the main documented benefit is physical fitness. The same South Korean lottery system showed that boys in all-male middle schools had significantly higher pass rates on standardized fitness tests compared to boys in coed schools [1]. The effect was substantial but did not hold for girls, indicating that the mechanism (perhaps more competitive or active peer culture) is gender-specific.

Academically, the picture is mixed. A study of Polish Catholic schools found that girls in all-girls schools scored about 17% of a standard deviation higher on science exams than girls in coed schools—a modest but meaningful edge on a high-stakes test that determines high school admissions [5]. However, a Zambian study found that students in single-sex schools generally performed better, but the authors attributed this to fewer distractions and discipline issues rather than any inherent academic advantage of single-sex teaching [6].

What is the hidden cost? Social skills and anxiety

The most consistent downside of single-sex schooling is its effect on cross-gender social skills. A rigorous longitudinal study in Hong Kong tracked students from their final year of high school to 1.5 years after graduation. Students from single-sex schools reported significantly lower confidence in their ability to form relationships with the opposite gender—an effect that persisted after graduation [3]. Importantly, this lower confidence predicted higher levels of mixed-gender anxiety over time, even after controlling for general social anxiety [3]. In plain terms: single-sex schooling may leave students less prepared for the mixed-gender workplaces and social environments they will encounter as adults.

This finding is especially notable because it held true across genders and sexual orientations, and the study used careful statistical matching to rule out pre-existing differences between students who choose single-sex versus coed schools [3]. The implication is clear: the social trade-off is real.

Does single-sex schooling affect mental health?

Yes, but the effects differ sharply by gender. A study of South Korean middle school students found that attending a single-sex school reduced the probability of depression among girls by about 9.9 percentage points—a large effect [4]. The same study found that girls in single-sex schools reported less stress related to peer relationships, suggesting that the social environment is less fraught without boys present [4]. For boys, however, there was no significant mental health benefit or drawback [4].

This gender asymmetry mirrors the physical fitness findings: single-sex environments seem to help girls emotionally and boys physically, but not the reverse. The takeaway is that the benefits are not universal—they depend on what outcome you care about and for whom.

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