121-127 Upchurch

prescriptions about the timing of first sex, vary to a great extent according to a youth’s gender and ethnicity.8 Most research has concentrated on females, partly because national fertility studies interview only females and because of the historical interest in teenage pregnancy. However, studies that have included both males and females have consistently shown gender differences in the age at first sexual experience.9 Explanations for the observed younger ages at first sex for males have centered on biological and maturational differences,10 variations in social controls, such as parental supervision,11 and differences in the opportunity costs of becoming sexually active (and the subsequent risk of unintended pregnancy).12 In addition, while 80% of a recent cohort of adolescents had had sex by age 20,13 normative expectations about the appropriate age and circumstances of first intercourse vary by gender.14 Theoretical explanations of ethnic differences in age at first sex tend to emphasize economic and sociocultural influences.15 The bulk of research has focused on understanding differences between blacks and whites, to some extent because of limitations in the degree of ethnic diversity in Dawn M. Upchurch is associate professor, Lené LevyStorms is a doctoral student and Carol S. Aneshensel is professor, all at the University of California, Los Angeles; Clea A. Sucoff is research associate, University of Minnesota. This analysis was supported by The California Wellness Foundation, grant 96-112; support for data collection was provided by National Institute of Mental Health grant 5R01 MH40831. Gender and Ethnic Differences in the Timing Of First Sexual Intercourse