Parents who quit early had children with 1.8 (OR = 1.80; 95% CI = 1.22, 2.64) times higher odds of quitting smoking for at least 1 month in young adulthood compared to those whose parents did not quit early. In contrast, there was no association (OR = 0.84; 95% CI = 0.47, 1.51) between parents quitting late and their young adult children's smoking cessation.