New evidence on the relationship between substance use and adolescent sexual behavior.

Policymakers and the public have a clear interest in encouraging teens to delay becoming sexually active or, if they are sexually active, to use birth control. Many researchers have argued that reducing substance use among teens will accomplish both of these goals, yet work in this area has failed to control for unobservables that are potentially correlated with substance use and sexual behavior. Using a variety of estimation techniques and data from National Longitudinal Study of Adolescent Health, we estimate the effects of marijuana and alcohol use on two outcomes: the probability of being sexually active, and the probability of having sex without contraception. Our results highlight the importance of controlling for unobservables and indicate that the link between substance use and sexual behavior is much weaker than previously suggested.

Black-white differences in social and economic consequences of obesity.

OBJECTIVE: To investigate social and economic effects of obesity for black and white females, and to explore possible explanations for race differences in obesity effects. SUBJECTS: 1354 non-Hispanic black and 3097 non-Hispanic, non-black, women aged 25-33y in 1990 from the National Longitudinal Survey of Youth 1979-1990. MEASUREMENTS: Body mass index (BMI) evaluated at age 17-24y (1982) and 25-33y (1990). METHODS: Logistic and linear regression of six labour market and marriage outcomes on early or attained BMI. Detailed controls for family socioeconomic background. RESULTS: Socioeconomic effects of obesity appear larger for whites than blacks. Obesity is associated with low self-esteem among whites, but not blacks. Differences in self-esteem do not account for race differences in the effects of obesity on socioeconomic status. Lower probability of marriage and lower earnings of husbands among those who marry account for the majority of the income differences between obese white women and those of recommended weight. Occupational differences account for more than one fifth of the effect of obesity on the hourly wages of both white and black women. CONCLUSION: Cultural differences may protect black women from the self-esteem loss associated with obesity for whites. However, differences in self-esteem do not account for the effects of obesity on socioeconomic status. Because the effect of obesity on the economic status of white women works primarily through marriage, it may therefore be less amenable to policy intervention to improve the labor market prospects of obese women.