Journal of Youth and Adolescence, Vol. 28, No. 4, 1999 Stability, Change and Individual Differences in Involvement with Friends and Romantic Partners Among Adolescent Females Melanie J. Zimmer-Gembeck 1 The initiation of romantic relationships is a normative developmental task among female adolescents. Friendships with other females may change as part of this task. Using structured interviews, this study collected data from 102 white females (ages 17 to 19) about their history of close peer relationships during high school. Trajectories of involvement (time spent) with close peers were examined using individual growth modeling. Females who increased time with romantic partners more rapidly also decreased time with friends more rapidly. Although most spent more time with partners than with friends at some time, the timing of this change and patterns of involvement with close peers varied. One-fourth of females spent more time with partners than with friends early in high school, but spent less time with friends than others did. Another one-half spent more time with partners than with friends later in high school, gradually increasing time with partners and reducing time with friends. Otherfemales never spent more time with partners than with friends, and maintained high involvement with friends and little involvement with partners. INTRODUCTION It has been suggested that the initiation of romantic relationships is a nor- mative developmental task of adolescence (Hartup, 1993; Havighurst, 1972). For most individuals, close, dyadic relationships with romantic partners are initiated during adolescence (Douvan and Adelson, 1966; Dunphy, 1963), and young people report spending increasing amounts of leisure time with their romantic partners or in cross-sex dyads as they mature (Csikszentmihalyi and Larson, 1984; Richards et al., 1998). Although a number of reports on general dating behavior during 1 Assistant Professor, Division of Medical Information and Outcomes Research, Oregon Health Sciences University, BICC, 3181 SW Sam Jackson Park Rd, Portland, OR 97201-3098; e-mail: zimmerge@ohsu.edu. 419 0047-2891/99/0800-4l9JI6.00/0 © 1999 Plenum Publishing Corporation