I couldn't help but notice that many of the comments on here were from mothers. I know that from a mothers point of view, cwintermote, these will be very helpful, but, if I may, I'd like to just speak from a daughters point of view.
I'm 16. I may not be fully sexually active, but I know that if my mum started trying to coax facts about my relationships out of me, I'd avoid the question. Not out of disrespect, but out of embarrasment, and partially, shame. I know that sounds strange, but I worry that my arents would be dissapointed in me. Perhaps your daughter is sharing some of my anxieties. And whilst you have every right to call it 'crap', becoming angry with her may not be the best way to deal with it. Tough love, yes, but anger will cause her to put up even more defences. I know it would me. What I'd like- personally- is for my mother to ask outright if I'd had sex. Tell me that it was ok if I had, but that she was upset because she was worried about my sexual health, and issues such as pregnancy. When you explain the reasons behind the anger, it makes it a lot easier for us to open up to you. If she still gives no response, that is the time to use the tough love, but I have no guidance for you there, I'm afraid.
With regards to the smoking, I'd just repeatedly warn her about the dangers. Constant drumming of facts into the brain might make her stop. There is probarbly a lot of peer pressure happening as well.
With your youngest, talk to her. Answer all the questions she has about sex and smoking, and answer them well. A majority of a girls sexual knowledge comes from what she's taught by adults, not friends. You need to really educate her about the dangers, and the negatives. If all this does not work, at least you know you've done all you could possibly do, and whatever choices she makes from that point are her own, and she will have to learn to deal with the consequences of poor decisions.
Hope this has kind of helped. Good luck,
Lauren. x