Estimating causal and time-varying effects of maternal smoking on youth smoking

•We use propensity score methods to estimate causal effects of maternal smoking.•This includes lifetime smoking (MLS) and prenatal tobacco exposure (PTE)•Both PTE and MLS have effects on youth smoking after propensity adjustment.•MLE’s effect on offspring smoking is stable across adolescence and young adulthood.•PTE’s effect is null in adolescence but becomes significant in young adulthood.