Validating an index of adolescent sexual behavior using psychosocial theory and social trait correlates.

Using a web-based survey of adolescents 14-16 years of age, a hierarchical index of heterosexual behavior was developed with excellent psychometric properties. The easiest sexual behavior to perform was "deep kissing" and the most difficult was "receiving anal sex" for females and "giving anal sex" for males. The index was validated with data that show increased sexual activity with being older and of minority status, with social traits such as physical development, having a romantic partner, and sensation seeking, and with psychosocial variables known to be associated with sexual behavior such as attitudes, norms, self-efficacy and intentions.