Early fertility has been linked to consistent negative effect on later life socio-economic and health outcomes, although effects are often substantially diminished once controlling for previous disadvantage. In this seminar I will present work on long-term effects of young parenthood on mental well being, drawing on data from the 1970 British Cohort Study and using a new, emerging, machine learning-based approach called Bayesian Additive Regression Trees (BART). The presentation will focus on the methods used, as well as share some very fresh preliminary results. For whom is young parenthood detrimental for later life health? Does early fertility have the same impact on young women across the population, or are there subpopulations for whom the event of early parenthood is more or less detrimental? This work is done in conjunction with collaborators from sociology and statistics at the University of Queensland.