High-Risk Sexual Behavior Among Heterosexual Undergraduates at a Midwestern University.(Statistical Data Included)

Approximately 80% of a self-selected sample of 593 heterosexual undergraduate college students studied at a large Midwestern state university in 1988 had ever experienced penile-vaginal or penile-anal intercourse. One-fifth of the 477 sexually experienced women and men said they had had heterosexual anal intercourse. The mean age at first vaginal intercourse was 17, while the mean age at first anal intercourse was about 18.5. Although less than four years, on average, had elapsed since the respondents' first vaginal or anal intercourse, females reported having had an average of 5.6 sexual partners, and males reported an average of 11.2 partners.

(Family Planning Perspectives, 24:116, 1992)

Although many sexually transmitted diseases (STDs) can be successfully treated and cured, the consequences of STD infection range from neoplasia, adverse pregnancy outcome and infertility in cases of syphilis, gonorrheal and chiamydial infections; to death in cases of human immunodeficiency virus (HIV) infection. (1) Data from the Centers for Disease Control (CDC) have documented a nationwide yearly increase in the rate of infectious syphilis, a growing proportion of infections with penicillin-resistant strains of gonorrhea, a high prevalence of chiamydial infection among persons of all socioeconomic strata (2) and a greater proportion of HIV infections associated with heterosexual transmission. (3)

The CDC has also estimated that two-thirds of the 12 million Americans infected with an STD each year are under the age of 25. (4) Consequently, public health officials have recognized that young adults, including the more than 13 million students attending colleges and universities in the United States, (5) are at high risk of STD infection. (6) The data in this article on the prevalence of high-risk sexual behaviors in a self-selected sample of undergraduate college students help to fill the large gap in knowledge about the sexual life-styles and practices of this vulnerable group of young Americans.

In general, age at first sexual intercourse and number of sexual partners are correlated with the risk of STD infection. (7) In addition, number of sexual partners and participation in "passive" (or receptive) penile-anal intercourse (hereafter referred to as anal intercourse) have been identified as the two primary sexual risk factors for HIV infection, (8) although HIV can also be transmitted, both from men to women and from women to men, by penile-vaginal intercourse (hereafter referred to as vaginal intercourse), (9) particularly if there is unprotected recurrent sexual contact with HIV-infected individuals. (10)

In most studies of sexual behavior, researchers have not defined such nonspecific terms as premarital intercourse, sexual intercourse, and coitus, the assumption being that study participants responded to these terms on the basis of vaginal sexual experience. Previous studies of sexual behavior have clearly shown that many college-age adolescents and young adults are sexually experienced. A study of U.S. high school students found that 48% of females and 61% of males have had sexual intercourse by the time they reach college age. (11) With each year of high school (grades 9-12) (12) and with increasing age (15-19), (13) there are significant increases in the proportion of adolescents who have had sexual intercourse. This pattern is reflected in studies of college students as well. (14) Thus, for each successive year of age or schooling, significantly more adolescents and young adults have engaged in sexual intercourse.

In general, studies of college and university students conducted between 1973 and 1988 indicate that 75-80% of males and 60-70% of females have engaged in intercourse. (15) Among the factors affecting the reported prevalence of intercourse among young adults is the year the study was conducted, since there is a general trend of increasing prevalence of sexual activity over time, particularly in the last decades. (16) Regional, cultural and ethnic variability(17) and varying methodologies also affect reported prevalence rates, but the general trend toward increased prevalence is usually seen whether the results are derived from small convenience samples (18) or from large national probability samples. (19)