To understand the etiology and consequences of child sexual abuse it is important to study the victims' subjective reactions to such incidents. Because researchers have not been able to survey children about sexual abuse, not much is known about how subjective reactions are related to gender, age, age difference, and the social relationship between the offender and victim. The present study fills this gap using data gathered from a large, nationally representative sample of Finnish children ages 11 to 17 (N = 32,145). Analyses of abuse are based on a sample of 1520 children (78% girls), while analyses of peer sexual experiences are based on a sample of 3551 children (55% girls). Multivariate analyses adjusted for the use of coercion, the intimacy of the sexual experience, and other incident characteristics. It was hypothesized that, as a result of sex differences in sexuality and attitudes toward deviant behavior, girls are more sensitive than boys to age and age difference. Three findings supported the hypothesis: (1) girls were more likely than boys to have a negative reaction to sexual encounters regardless of the age difference; (2) for girls, age was negatively associated with the likelihood of a negative reaction, but age had no effect for boys; and (3) girls reacted negatively to age difference while boys did not. However, girls did not react more negatively unless the offender was at least eight years older. The results highlight the susceptibility of adolescent boys to encounters with older women. They further suggest that ignoring the role of the victim limits understanding of the vulnerability of young people to sexual abuse.