Adolescent motherhood and the development of adolescent Offspring: Examining the role of selection versus early environmental factors.

Background: The study examines the adolescent developmental outcomes in education, mental health, and physical health of children born to teenage mothers at the start of the millennium. Objective: It aims to understand the extent to which long-term developmental outcomes of children born to adolescent mothers are due to selection effects versus other factors. Methods: It uses longitudinal data from the UK Millennium Cohort Study. Multivariate regressions examine the extent to which the association between maternal age at birth and adolescent outcomes is explained by selection into teenage motherhood, and how the relationship is mediated by the early environment and maternal behaviours. Results: Teenage mothers are disadvantaged in terms of their backgrounds, and their children faced more adversity in their early environment. An unadjusted comparison shows that their adolescent offspring have lower academic achievement, and are more likely to be overweight or obese, but there are no differences in their socio-emotional adjustment. The 'penalty' from teenage motherhood in excess weight is due to negative selection into teenage motherhood. However, the differences in educational attainment of adolescents born to teenage and older mothers reflect both pre-childbearing selection and differences in the child's early environment. A decomposition analysis shows that maternal age accounts for only a low proportion of the variance in adolescent development. Contribution: The study provides the first evidence on long-term outcomes of children born to teenage mothers for the UK. It studies the entire range of key developmental outcomes. It uses a novel decomposition to examine the relative importance of different variables for explaining variation in the outcomes of interest.