Introduction:
To ascertain the prevalence of tobacco use among parents of secondary school students and their opinions regarding the factors that influence the start of tobacco use, which substance is more harmful than cannabis or tobacco, their beliefs about the effects of e-cigarettes and their influence on the start of traditional tobacco use in their children.

Material and Methods:
Cross-sectional epidemiologic study, in which the information was primarily gathered through a self-administered survey of a sample of 304 parents from the "Joan Fuster" secondary school in Sueca (Valencia).

Results:
The average age of the parents surveyed and who responded was 45.3 years, 72.36% of them being female. 36.51% declared themselves non-smokers, 27.30% ex-smokers, 9.8% occasional smokers (not daily smokers), and 26.31% daily smokers. Regarding the belief about the factors that influence the onset of smoking in their children, the most influential factor in the onset of smoking in their children is that their friends do it, with 90.13% of parents, followed by alcohol consumption (82.56%), and that the parents are smokers (72.3%), while the lack of sports practice was prioritised as a problem by 60.19%. With regard to which substance they consider most harmful, 14.8% believed cannabis, 11.51% tobacco and 73.68% both equally. 71.05% did consider e-cigarettes to be harmful, 7.56% did not and 21.38% did not know. And 69.73% of parents do believe that e-cigarettes can influence their children to start smoking traditional tobacco.

Conclusions:
The majority of parents surveyed were non-smokers, although there is a very high prevalence of ex-smokers. The majority of respondents believe that the most important factor for their children to start smoking is that their friends have a smoking habit, but they underestimate the fact that they themselves are or may have been smokers. Tobacco use is perceived as less harmful than cannabis use, and a lack of knowledge about the dangers of tobacco use also emerges. With regard to e-cigarettes, they do show a relatively high level of knowledge about the harms of e-cigarettes, although a significant percentage say that they are still unsure about this aspect.