The public health community has voiced strong concern over the incidence of sexually transmitted infections and unwanted pregnancies among adolescent girls, ranking increased condom use among adolescent girls as a top priority for the decade (DHHS, 2000). Yet relatively little is known about the psychosocial antecedents of girls'sexual risk-taking behaviors, or about how these practices develop and change over time. The proposed research fills this gap by examining how sociocultural values which define the kinds of behaviors that are expected for adolescent girls (i.e., femininity ideology) contribute to adolescent girls'sexual risk taking behaviors. This research investigates the role of three specific aspects of femininity ideology (i.e., self-silencing, self-objectification, and romance conventions), in the development of adolescent girls'sexual risk-taking behaviors. Through a secondary data analysis of data collected in two longitudinal studies of 587 early adolescent (ages 13-14), middle adolescent (ages 15-16) and late adolescent girls (ages 17-18), the proposed project will investigate the following specific aims: (1) to examine how femininity ideology influences the timing of girls'first experience of sexual intercourse (coital debut) as well as the development of sexual risk-taking behaviors (i.e., condom use and contraceptive use) over the course of adolescence;(2) to compare associations between femininity ideology and sexual risk-taking across the transition from early to middle adolescence to associations across the transition from middle to late adolescence;(3) to test emotional and sexual mechanisms by which femininity ideology contributes to sexual risk-taking;(4) to compare the effects of femininity ideology on sexual risk-taking in the two different racial/ethnic groups of adolescent girls (i.e., White and Latina) who are the most vulnerable to accepting conventional ideas about femininity ideology. Distinct statistical modeling techniques (i.e., multivariate latent growth curve modeling and multi-group path analysis) will be used to address the four specific aims. The proposed research provides a new, developmental perspective that is crucial in order to deepen our understanding of the factors that put sexually active adolescent girls at high risk for STIs and unintended pregnancies. Project Narrative: The health risks that stem from adolescent girls'sexual risk-taking behaviors have significant public health consequences. Previous research has overemphasized demographic correlates of sexual risk-taking such as ethnicity and socioeconomic status, yet these factors are rarely subject to change and provide little opportunity for intervention. This innovative project will fill this significant gap in previous research by testing a new, developmental model of sexual risk-taking that includes gendered components that are specific to adolescent girls. An empirical understanding of how conventional ideas of femininity ideology contribute to girls'risk-taking behaviors is essential to helping us understand and prevent the continuing epidemic of STIs and unwanted pregnancies among adolescent girls in the United States.