Table 1 shows the grade at first participation in alcohol drinking, cigarette smoking, and sexual intercourse by gender. Overall, the lifetime prevalence for alcohol drinking (61.9% of males vs. 61.1% of females, p = 0.034), cigarette smoking (32.0% vs. 22.1%, p < 0.001), and sexual intercourse (6.4% vs. 3.2%, p < 0.001) was higher in males than in females. In addition, more males than females reported consuming alcohol (19.9% of males vs. 15.2% of females, p < 0.001), smoking tobacco (13.2% vs. 7.9%, p < 0.001), and having sexual intercourse (1.1% vs. 0.4%, p < 0.001) before attending middle school (preteen initiators).
