This study from the journal Psychology of Addictive Behaviors found:
Children’s risk of marijuana and alcohol use and attitudes toward marijuana were influenced by their parents’ marijuana use pattern over time.
Children whose parents used marijuana primarily during adolescence/early adulthood and those whose parents continued to use marijuana from adolescence through adulthood were at highest risk.

Abstract:
Diverse patterns of life-course marijuana use may have differential health impacts for the children of users. Data are drawn from an intergenerational study of 426 families that included a parent, their oldest biological child, and (where appropriate) another caregiver who were interviewed 10 times from 2002 to 2018; the current study used data from 380 families in waves 6-10. Analyses linked parent marijuana use trajectories estimated in a previous publication (Epstein et al., 2015) to child marijuana, alcohol, and nicotine use; promarijuana norms; internalizing; externalizing; attention problems; and grades using multilevel modeling among children ages 6 to 21.

Four trajectories had been found in the previous study: nonuser, chronic, adolescent-limited, and late-onset. Results indicate that children of parents in the groups that initiated marijuana use in adolescence (chronic and adolescent-limited) were most likely to use substances. Children of parents in the late-onset group, where parents initiated use in young adulthood, were not at increased risk for substance use but were more likely to have attention problems and lower grades. Results held when parent current marijuana use was added to the models. Implications of this work highlight the importance of considering both current use and use history in intergenerational transmission of marijuana use, and the need to address parent use history in family based prevention. Prevention of adolescent marijuana use remains a priority.