The conceptual model underlying our study is based on the TpB. Attitude, an individual’s positive or negative belief about performing a specific behavior, together with subjective norms, the beliefs that specific individuals will approve or disapprove of the intended behavior were the first two determinants described as predicting behavior in the Theory of Reasoned Action. Recognizing that individuals have varying degrees of control, from total control to total lack of control, the determinant of perceived behavioral control, was added and the theory renamed as the TpB (Ajzen, 2005a). This model was identified as the TpB model in this study (See Fig. 1). Age, parent–adolescent communication and perceived risks of sexual behavior were added into the TpB model based on the Ajzen’s guidance of adding variables (Ajzen, 2005b). The model in Fig. 2 refers to the alternative model in this study and the shaded variables indicate additional variables that, with variables in the baseline model, form the alternative model.