Riskonnected: Social Media and Puberty in the UK

We examine the association between intensive social media use and puberty timing,particularly earlier menarche in girls. Using data from the Millennium Cohort Study(MCS), a nationally representative longitudinal dataset tracking around 19,000 childrenin the UK, we analyse how digital engagement influences adolescent development. Ourresults show that intensive social media use is significantly associated with menarche ac-celeration in girls but has no clear association with male puberty markers. The likelymechanism behind this relationship is the negative association between social media andmental health, particularly stress and anxiety, which have both been linked to earliermenarche. Our findings highlight social media use itself as a potential risky behaviour,reinforcing concerns about its effects on adolescent well-being. JEL Codes: I12, I31, J13, J16