The Impact of Classroom Gender Composition on Mental Health of Adolescents: Evidence from the Czech Republic

Abstract: This essay investigates the impact of classroom gender composition on the mental health of adolescent students. Using data from the Health Behaviours of School-aged Children survey in the Czech Republic, we exploit idiosyncratic classroom variation in the gender composition within the same schools across different grades. We find that a higher proportion of female peers in the classroom has a detrimental effect on male students’ mental health, whereas no comparable effects are observed among their female counterparts. Specifically, this effect is primarily driven by an increase in symptoms such as feeling low and nervous. Importantly, our study reveals non-linearity in the classroom gender composition effects, suggesting that a reduction of the number of girls in the classroom may not always be advantageous for boys, as its effectiveness depends on the initial gender composition.