This cross-sectional study examined the relationship among maternal HIV, pubertal development, gender, ethnicity, and spirituality and adolescent participation in sexual possibility situations (SPSs) and in sexual activity. SPSs are social encounters with cross-gender peers that afford the opportunity to engage in sexual activity. Heterosexual African American and Latino adolescents (10 to 14 years) and their HIV-positive or HIV-negative mothers (N = 176) were interviewed about risk and protective factors related to sexual behavior. Results indicate that physically mature adolescents are more likely to participate in SPSs, that girls are less likely than boys to participate in SPSs, and that more spiritual adolescents are less likely to participate in SPSs. Increased time in SPSs is associated with engagement in sexual behavior, and family religiosity is associated with decreased probability of sexual behavior. Mothers' HIV status was not associated with SPS participation or engagement in sexual behavior. Suggestions about further refinement of research using SPSs are explored. (Contains 6 tables.)