The Postponing Sexual Involvement (PSI) program is a school-based program designed to delay sexual activity among adolescents. The curriculum was widely introduced into the Atlanta public schools in 1985 and was taught to eighth graders by health educators, nurses, and adolescent counselors using teens as primary presenters. The PSI program was developed to complement the knowledge-based sex education course "Human Sexuality", and is based on the "social influence" theory, which holds that young people are more likely to become sexually involved because of social and peer pressures than because of a lack of knowledge about sexuality and sexual activity. PSI uses activities that help identify the origins of pressure to engage in sexual activity, examines the motivations behind that pressure, and helps students develop skills to respond to that pressure effectively. The program is also built on research that shows that teenage leaders produce greater and more lasting effects on other teens' behavior than do adults.

The goal of this program is to delay sexual activity among adolescents.

In an evaluation of the pilot PSI program in Atlanta, students from 24 schools that received PSI were compared to students from 29 control schools in the area that received those schools' regular sexual education program. Among students who had not had sexual intercourse prior to the program, students in the control group were five times more likely to have begun having sex than were PSI students (20 percent versus 4 percent) by the end of eighth grade. By the beginning of ninth grade, the difference between these rates was still significant at 27 percent and 12 percent, respectively. By the end of ninth grade, the difference between groups was still significant, with rates of 39 percent versus 24 percent. At the end of eighth grade, females in the control group were significantly more likely than students in the PSI group to have engaged in sexual intercourse (15 percent versus 1 percent). The differences between groups remained statistically significant in the ninth grade, with rates of 18 percent versus 7 percent at the beginning of the school year, and 27 percent versus 17 percent by the end of the school year. Male students in the control group were significantly more likely to have engaged in sexual intercourse by the end of eighth grade (29 percent versus 8 percent), with rates of 42 percent versus 22 percent at the beginning of ninth grade, and 61 percent versus 39 percent at the end of ninth grade.