I don't smoke, and I never have. I tried a cigarette when I was about 7-ish. My mom had fallen asleep on the couch, a cigarette still lit in the ashtray, so I thought I'd try it. I haven't touched one since. I even refused to buy them for my family once I got old enough.
Both of my parents smoke, my brother and his wife smoke, and three of my four grandparents smoked. The other one chewed. I grew up around smoke, so it doesn't bother me as long as it doesn't get directly in my face, or there's a lot of smokers in a closed-in area. I was in a mobile home with 3 smokers once, one being my mom, and I had to leave after about a half hour because the smoke got to be too much, and made my eyes hurt and water. When they visit me, they go outside to smoke, even though I've never actually asked them.
I've had mixed reactions with pregnant women and smoking. I live 20 minutes from my in-laws (mother, brother, and his wife), and 10 hours from my mom, brother, and his wife. Both wives were pregnant at the same time. The whole family was after my husband's brother's wife to stop smoking during his wife's pregnancy. When I went up to visit my family for Christmas, I saw my brother's wife light up. Being in the habit of reprimanding, I made a comment to her. My mom turned to me and told me not to say anything, since it wasn't my baby. So I didn't say anything about it the rest of the stay. Her reasoning was that since she smoked all during her pregnancies with me and my brother, and we turned out fine (physically.. I don't put too much store into my brother's mental state

), I didn't have a whole lot of room to talk.