Attitudes toward premarital sexual behavior, lifetime prevalence of sexual activity, and the variation in exposure to sexual intercourse is described. The main focus is on the number of sex partners and the social context of partner change. The variation by social and demographic characteristics in the number of sex partners is analyzed. Despite considerable variation in partner change behavior among the women, the relative pervasiveness of this behavior across social and demographic categories is notable. The influence of the exposure variables stand out. The number of sex partners steadily increases with increasing length of exposure.