First Sexual Intercourse and Adolescent Well-Being

First sexual intercourse is a socially embedded milestone that may both reflect and shape well-being. Using up to ~6,800 participants followed across as many as 15 annual waves, we tested selection and socialization for self-esteem, life satisfaction, and depressiveness. We examined selection with logistic, linear, and Cox models, and socialization using event-centered fixed-effects models. Moderators included gender, relationship status/satisfaction, physical attractiveness (selection), and age at first intercourse (socialization). Static well-being levels showed inconsistent links to timing. However, adolescents who barely changed or increased slightly in self-esteem, life satisfaction, and depressiveness started earlier, whereas larger swings in either direction coincided with postponement. For socialization, we found a small post-event lift in life satisfaction, driven by partnered adolescents. Overall, first intercourse appears to express ongoing trajectories more than it transforms them. Findings are interpreted through a developmental-task lens, challenge risk-centric narratives, and suggest emphasizing relationship context over sexual onset per se.