Selected behaviors that increase risk for HIV infection, other sexually transmitted diseases, and unintended pregnancy among high school students--United States, 1991.

Since the 1970s, sexual activity has increased among adolescents in the United States (1); at the same time, rates of sexually transmitted diseases (STDs) (1), unintended pregnancy (2), and--beginning in the 1980s--human immunodeficiency virus (HIV) infection (3,4) also have increased among adolescents. This report presents 1991 self-reported data from students in grades 9-12 about behaviors that can result in HIV infection, other STDs, or unintended pregnancy.