with four or more partners, being sexually active (intercourse during the three months prior to the survey), or having used alcohol or drugs before last sexual intercourse remained constant (CDC, 1995). These data suggest that HIV and other STD prevention activities targeted towards adolescents beginning in the mid- to late 1980s in response to the HIV epidemic may have had a positive effect on some aspects of adolescent sexual activity.
Sexual activity among adolescents is sometimes initiated before the teenage years. A 1992 survey of 2,248 students in grades 6, 8, and 10 from an urban public school district found that 28 percent of sixth-graders and one-half of eighth-graders reported ever having had sexual intercourse (Barone et al., 1996). In an effort to examine the determinants of early onset of sexual intercourse among high-risk adolescents, Mott and colleagues (1996) analyzed a series of data collected through the National Longitudinal Survey of Youth from 1988 through 1992. They found that children were more likely to have early onset of intercourse if their mother had sex at an early age and if she worked extensively.