ORIGINAL ARTICLE Older Boyfriends and Girlfriends Increase Risk of Sexual Initiation in Young Adolescents BARBARA VANOSS MARI ´ N, Ph.D., KARIN K. COYLE, Ph.D., CYNTHIA A. G ´ OMEZ, Ph.D., SCOTT C. CARVAJAL, Ph.D., AND DOUGLAS B. KIRBY, Ph.D. Purpose: To explore the prevalence and impact of older boyfriends or girlfriends on sexual behavior in sixth graders (mean age 11.5 years). Methods: Students in 19 ethnically diverse middle schools in an urban area were surveyed (n  2829, response rate 68%). Instrument measured demographics, age of oldest boyfriend or girlfriend, unwanted sexual advances, peer norms, and sexual behavior. Students with older, same-age, or no boyfriend or girlfriend were compared on demographic and psychosocial variables using analysis of variance. Separate multivariate logistic regressions for both boys and girls were used to predict sexual behavior from demographics, psychosocial vari- ables, and age categories of boyfriend or girlfriend. Results: One-half of the respondents (56%) had never had a serious boyfriend or girlfriend, 35% reported that their oldest boyfriend or girlfriend was <2 years older than they, and 8.5% reported a partner >2 years older. Those reporting an older boyfriend or girlfriend were more likely to be Hispanic, were less acculturated, re- ported more unwanted sexual advances and more friends who were sexually active, and, among girls, were more likely to have experienced menarche. Overall, 4% of students reported ever having had sex. Students with an older boyfriend or girlfriend were over 30 times more likely than those with no boyfriend or girlfriend ever to have had sex (odds ratio  33.8 for boys and 44.2 for girls). In the multivariate logistic regressions, peer norms about sexual behavior, having experienced unwanted sexual advances, and having a boyfriend or girlfriend were strongly associated with having had sex. Conclusions: Having an older boyfriend or girlfriend, although rare, is associated with early sexual onset and unwanted sexual activity in this population of sixth graders. © Society for Adolescent Medicine, 2000 KEY WORDS: Acculturation Adolescent Ethnic differences Gender differences Older partner Sexual behavior Sexual initiation Early or precocious sexual activity is an important predictor of sexual health risk. Young women who initiate sexual intercourse before age 16 years report a higher number of lifetime sexual partners and more recent sexual partners than those who initiate later (1–3). Similarly, early sexual initiators are less likely than later initiators to use a condom regularly (3). Earlier age at first sex is associated with more sexual risk behavior (4), more sexually transmitted diseases (STDs) and human immunodeficiency virus (HIV) (5), teen pregnancy (3,6), and abuse. Researchers have sought to understand early sexual initiation because of its strong association with these negative health consequences. Antecedents of early sexual activity that have received the most attention are immutable, related to a larger social context, or of only moderate predictive value (7–9). Many of the most studied predictors of early sexual initiation (ethnicity, income, family From the Department of Medicine, University of California, San Francisco, AIDS Research Institute, Center for AIDS Prevention Studies (B.V.M., C.A.G.), San Francisco, California; and ETR Associates (K.K.C., S.C.C., D.B.K.), Scotts Valley, California Address correspondence to: Barbara VanOss Marin, Ph.D., Univer- sity of California, San Francisco, Center for AIDS Prevention Studies, AIDS Research Institute, 74 New Montgomery, Suite 600, San Fran- cisco, California 94105. Manuscript accepted January 20, 2000. JOURNAL OF ADOLESCENT HEALTH 2000;27:409– 418 © Society for Adolescent Medicine, 2000 Published by Elsevier Science Inc., 655 Avenue of the Americas, New York, NY 10010 1054-139X/00/$–see front matter PII S1054-139X(00)00097-5