Interestingly, this study found that parental approval of smoking was a factor influencing the susceptible pre-contemplation stage, which is the earliest smoking stage. However, previous studies found parental approval effects the later stages of smoking uptake (regular and established smoking). This difference may have been due to the different cultural backgrounds among the subjects. In the Thai culture, children generally have a close relationship with parents and are expected, due to social norms, to obey their parents. Thus, before peer influences increase, Thai adolescents may remain relatively sensitive to their parents’ values and expectations