A comprehensive study conducted in France analyzing the mathematical performance of nearly 3 million first and second grade students reveals that boys and girls start school with similar math abilities, but a gender gap favoring boys emerges after just four months of formal schooling. This gap continues to widen over time, with boys increasingly outperforming girls by the beginning of second grade. The study attributes the emergence of this disparity to cultural stereotypes and educational practices that may reinforce inequalities and induce anxiety in girls from an early age. The research highlights that the difference is not due to innate ability but rather to systemic factors within the school environment, including competitive and time-pressured teaching and testing methods that girls are socialized to fear. The findings underscore the need for targeted efforts by schools, parents, and researchers to address these early disparities and consider alternative teaching approaches to close the gender gap in mathematics.