In the United States, about 80 percent of young people have had sexual intercourse at some point during their teenage years (Singh and Darroch 1999). A number of sexual behaviors vary by race/ethnicity: 30 percent of black male youth report having had intercourse before age 13, and 48 percent report having had four or more sex partners, compared with 12 percent of white male youth and 23 percent of Hispanic male youth (CDC 2000). One important, but poorly understood, pathway that shapes sexual practice is religion. Religion is a vital part of many adolescents' lives, and it, too, varies by race/ethnicity: 55 percent of African American youth say religion is very important to them, compared with only 24 percent of white youth (Johnston et al. 1999). Only recently have the demographic, medical, and public health communities taken an interest in the association between religion and health practices. There are numerous ways in which religion could (as distinct from does) affect adolescent sexuality and its practice: it may factor into attitudes and beliefs about contraception, permissible premarital sexual activities, use of pornography, and homosexuality, as well as indirectly affect sexual behavior through its effects on friendship choices (i.e., selection), dating patterns, etc. (Wallace and Williams 1997). How religion ultimately contributes to such sexual values and behaviors in these ways is not as well known as this list of possible relationships may infer. Moreover, there have been few thorough race/ethnic comparisons of the relationship between religion and sexual behavior - despite religion's clear differences by race/ethnicity- and even fewer explanations offered for the relationships that are known. This proposed project takes a solid step in the direction of deciphering those relationships and pursuing explanations by synthesizing a conceptual model about mediated and contingent religious effects on sexual behavior- effects that are thought to be subject to both personal attitudes about sex as well as school "climates" about normative sexual behavior - with rich individual, network, and school data from the National Longitudinal Study of Adolescent Health, supplemented by new data from the National Study of Youth and Religion (NSYR).