Former neighbor kids of mine (current days about 30 -40 years old) were an example of an often heard saying. That see smoking, and live around smokers will most certain led to smoking yourself. They grew up with parents who both smoke, and simply couldn't (or wouldn't) manage to stop the habit. Their children started smoking as teenagers, besides veto's, promises, requirements of their parents etc etc. As far as I know they still smoke.
My parents both smoked, my mother only in her early 20s (now and then) while my father smoked until somewhere in his 40s. As they put it in the past smoking was considered to be normal, even cans with cigarettes on the table at parties. My dad has quit smoking by using his own wil power. Up to present he never went back to smoking. And other people are allowed to smoke in his vicinity or house, but he himself thinks it is nasty. We, their children, reacted differently. From having no urge or curiosity to smoke at all till being a party/event smoker. One of my brothers belonged to the last group and the reason why I has quit smoking is a funny anekdote (if it is true what he told us). Apparently one night going out he hadn't smoked (yet) and went on kissing a girl who had smoked earlier that night. According to him he found the taste of smoke and such during the kiss very disgusting. And as he came to the conclusion he would taste and smell the same after smoking he decided to quit.