urveys in Western countries suggest that members of recent birth cohorts are consuming more alcohol at younger ages than preceding cohorts. 1 The patterns of drinking also appear to have changed, with recent cohorts in the United States reporting more frequent heavy drinking at younger ages but reduced alcohol use at later ages. 2,3 In Australia, less sophisticated analyses of cross-sectional surveys over time suggest that initiation of drinking has occurred at increasingly earlier ages 4 and that risky alcohol consumption among youth has increased. 5,6 Especially noteworthy in the increasing alcohol use among young cohorts is increased drinking among young females. 1 There was a large increase in high-risk drinking among girls 14 to 17 years of age (1%-9%) in Australia between 1998 and 2001, while levels of drinking in men 18 to 24 years of age decreased. 7 In the United Kingdom, the prevalence of alcohol misuse increased in those aged 18 to 24 years during the 1990s, particularly among women. 8 Likewise, data from the Netherlands twin registry show that alcohol consumption increased among adolescents between 1993 and 2005 to 2008, with the sharpest increase in girls aged 12 to 15 years. 9 Quantifying generational trends using repeated crosssectional survey data is challenging. The use of different survey questions at different periods means that the rates of al-IMPORTANCE Increases in alcohol use in young women over recent decades are shown by national survey data but have yet to be replicated using prospective data. OBJECTIVE To compare change in alcohol use over a generation of young women born in Australia from 1981 to 1983 at 21 years with that of their mothers at the same age. DESIGN, SETTING, AND PARTICIPANTS Data came from the Mater University Study of Pregnancy, a prospective prebirth cohort study that recruited all pregnant mothers attending a hospital in Brisbane, Australia, from 1981 to 1983. The analyses were restricted to 1053 mothers who were aged 18 to 25 years of age at the baseline measurement and their daughters who were between the same ages when assessed 21 years later. MAIN OUTCOME AND MEASURE Assessing the increase in the same prospective measures of 4 levels of alcohol use between mothers and daughters. RESULTS Multinomial logistic regression for clustered data indicated daughters were at greater odds of consuming high (odds ratio [OR] = 5.68 [95% CI, 4.24-7.57]) and moderate (OR = 2.81 [95% CI, 2.18-3.63]) levels of alcohol than their mothers. Not having a dependent child roughly doubled the odds of all levels of drinking in both cohorts. Undertaking or completing tertiary education had no effect on consumption. There was an interaction between mothers' or daughters' drinking and partner status (χ 2 3 = 12.56; P = .007); having a partner doubled the daughters' odds of consuming high levels of alcohol (no partner: OR = 0.51 [95% CI, 0.31-0.80]) while the odds of drinking at the highest level were more than 5 times for mothers who were single (OR = 5.65 [95% CI, 2.99-12.35]). CONCLUSIONS A...