Sex education is integral to helping protect adolescents and young adults from sexually transmitted infections, avoid unwanted pregnancies, and build healthy intimate relationships. The aim of this study was to examine gender differences in sex-related knowledge, attitudes, and behaviors, and to identify factors that may contribute to these differences. A cross-sectional survey was distributed to 190 adolescents from three middle schools and one senior high school in Fuzhou, China. Multivariable logistic regression analyses were used to determine the associations between individual factors and students' attitudes or behaviors. Parents were more likely to answer girls' questions about sex than boys' questions (p < 0.001), and sex education courses were delivered later to boys (p = 0.003) than to girls. Accordingly, girls were more positive than boys when they encountered issues related to puberty (p < 0.001) and when participating in friends' discussions about puberty and adolescence (p = 0.004). Girls were less likely to accept intimate behavior (sexual touch/intercourse) than boys (p = 0.011). In the multivariable logistic regression model, gender and parents' reactions to the students' questions were independent factors in their styles of coping with puberty-related issues. However, gender was not associated with students' reactions to friends' discussions about puberty or their acceptance of intimate behavior in the adjusted model, while other variables, such as knowledge score and need score, were identified as independent factors. Our study found that several individual factors may explain gender differences in adolescents' attitudes and behaviors about sex. Designation of targeted sex education programs should consider these individual factors in the future. [ABSTRACT FROM AUTHOR]