Adolescents' sexual risk-taking has been conceptualized in various ways: early age at first intercourse, number of partners, type of partner or length of relationship, frequency of intercourse, consistency of condom use, and use of other methods of birth control. Although each can be considered an aspect of risk taking, none by itself is valid as an operationalization of risky behavior (Metzler, Noell, & Biglan, 1992; Sieving et al., 1997). Rather, each is a proxy--a measure that captures some of the variance in risk-taking but does not in itself completely measure the construct. The reason that none of these factors completely represents risk-taking is that sexual behavior always involves a combination of them. The characteristics of this combination determine whether a particular pattern of behavior is safe or risky with regard to disease prevention or pregnancy. For example, the risk of STD acquisition from inconsistent condom use may be minimal with one partner, like in a mutually monogamous relationship, if neither partner is infected. However, risk would become greater with larger partner numbers because the risk of coming across an infected individual increases. Similarly, disease risk from condom non-use increases with larger number of intercourse occasions, especially if occurring with multiple partners. In terms of pregnancy, each additional act of unprotected intercourse increases risk.
