A majority of adolescents initiate sexual activity by the time they reach age 18 (for a review, see Willetts, Sprecher, & Beck, 2004). Because teens generally are not consistent users of contraception, however, negative outcomes can result from teenage sex, including unintended pregnancies, HIV, and other sexually transmitted diseases (STDs; e.g., Upchurch & Kusunoki, 2006). These health risks have contributed to adolescent sexuality moving from being a "private, family matter" to being considered a "public health issue" (Advocates for Youth, 2006). In a search for factors that can contribute to delayed onset of sexual activities as well as more responsible sexual behavior when adolescent sex does occur, health care practitioners, researchers, and educators have focused on the importance of sex education and communication, within both the formal school system and the family (Carroll et al., 1999; Feetham, 1997). The major purpose of this research was to analyze data that have been collected within one university setting over almost two decades in order to examine cohort changes and other influences on university students' perceptions of the sources of their sex education and the degree to which they communicate about sex with various others.
A Conceptual Background
In the study of teen and young adult sexuality, many sexuality variables have been examined (e.g., sexual desire, sexual attitudes, sexual behavior, sexual knowledge, sexual problems), with a consideration of explanatory variables from diverse theoretical perspectives originating in multiple disciplines (Weis, 1998). Our research is guided by a sociological perspective including the theoretical models of Christopher (2001) and DeLamater (1987). One major assumption of a sociological perspective is that every society regulates the sexuality of its members (DeLamater, 1987). Basic institutions in society such as religion and family influence societal members' sexuality, including the ease with which sex information is transmitted. As noted by DeLamater (1987, 1989), societal influences on sexuality operate at multiple levels. Most distal are macro-level influences, including broad historical changes. The next level is subcultural, which includes social class and ethnic background. The interpersonal level includes interactions with significant others such as parents and peers. Macro-, subcultural-, and interpersonal-level variables then affect variables at the individual level, such as sexual desire, sexual attitudes, and sexual knowledge.
In the present study, we examine young adults' perceptions of interpersonal-level influences on their sexual knowledge, as well as the degree to which young adults report communicating about sex with others. In addition, we consider distal influences on the interpersonal level of sex communication and transmission of sex education by examining the influence of macro and subcultural variables on reports of sources of sex education and targets of one's communication about sex. In a model presented by Christopher (2001), family, media, and peer groups are the major social agents that affect sexual knowledge. In this study, we consider their influence, the influence of the educational and medical institutions, as well as the influence of a macro-level influence (historical time).
In the literature on sex education from parents to teens, sex education often is referred to interchangeably with sex communication (Fisher, 2004). It is assumed that if parents communicate about sex with their children, they are providing sex education. Not all communication about sex provides sex education, however; in addition, whereas sex education usually is characterized by the unilateral transfer of information from the one who knows more to the one who knows less, sex communication can be initiated by either party and generally is mutual (e.g., Warren, 2006). Our study makes an important contribution …