I have another example: my father smoke a lot. I don't smoke and never try, but my brother smoke. I don't think only family influences on a person, it depends on many other things (may be some stress situation) or people who are near .So my parents don't smoke but I do. My cousin's parents smoke and she doesn't. I can find a thread here: I never felt smoke at home so for me to test a cigarette was something new, interested that I have never tasted before. She (my cousin) inhaled smoke since her childhood and she started to hate it inside her mind and she understood by her second ego she would never smoke. So she doesn't smoke now.
Of course, smoking is not good, but every person makes his own choice. It's neccessary to give an advice to the person who begin smoke, but not prohibit!