Smoking and doing coke are not natural parts of human experience. They are not something nearly everyone will inevitably do at some point in their life. It's possible to explain coke and smoking in a "these things are terrible and you should never ever do them" way, which you cannot do with sex.
Smoking and doing coke are, inherently, always harmful and stupid. Sex is not inherently harmful and stupid. If your child feels sexual, then telling him he's too young to have those feelings will make him feel guilty, like there's something wrong with him. It will plant the seed that those feelings are dirty and that he should repress them. Do you have any idea what kind of psychological damage that will cause him for years to come, possibly the rest of his life?
I haven't read till the end of this thread, so I'm not certain if anyone remembers this point in the conversation, but I had to react to this psycological damage point...
As someone who is still quite young (I'm 18 and only just left home for uni) I completely agree with this post. I was raised in a very conservative family, where we NEVER talked about sex, in any way, shape, or form, besides "don't do it, it's bad, you can get pregnant." I learned about the technicalities of sex through sex ed in middle school, which basically consisted of a million different scare tactics from videos of childbirth to disgusting pictures of STDs, all reinforcing the idea that sex was dirty, bad, and dangerous.
I met BoyF when I was just 14 and started dating him a few months later, right after turning 15. I was extremely uncomfortable with my sexuality and sex, and had had an exciting but simultaneously shaming kiss with a girl at camp, which I was so convinced was wrong that I buried it deeply, causing only more tension in my attitude towards sex and sexuality. Gays were a joke in my family, and I barely thought about lesbians or bisexuals. BoyF and I, being obviously quite hyped-up with hormones and teenage excitement, began enthusiastically exploring our sexuality with each other, at a pace that was comfortable and wanted by both of us, in what I think was an extremely healthy way for two teenagers....
Until several months into our relationship, several after we had realized we were in love with each other, when my father found a private letter I had written to BoyF in which I stated that I wanted to "make love," and proceeded to talk about all the things we had done and why I loved doing them. I wasn't even specifically talking about having sex, but the memory of my parents confronting me, yelling at me, telling me I had to stop doing those things, telling me I had to take things slower with BoyF so I could enjoy it, telling me they understood my urges but I needed to repress them (which is horribly, horribly hypocritical), and so on... they weren't even terribly hurtful things to say, yet I still feel that pain sitting here, though it was nearly 3 years ago.
From then on a reluctance to sex built up in me, and a constant, pervasive nervousness that made it impossible for me to enjoy sex, have sex in a truly emotional and intimate way, even to climax... I lost my virginity to BoyF after 8 months together, when it felt right for both of us and I knew I loved him enough to not regret it even if we weren't together forever; but throughout our sex life, the times when I was truly relaxed and enjoying myself were few and far between. At times when I should have been bonding and getting to understand my body, I felt wracked with guilt and confusion, my mind a constant battle between what I felt and what I was told I should feel.
I felt these feelings of guilt until I left home and came to university - I was a senior in high school, I was in a wonderful, long-term relationship with a man who was good to me, clean, and sexy to boot. We used condoms, I was on the pill, I was making big, important decisions about the rest of my life, I was practically an adult, yet I couldn't do exactly what I wanted to do with my own body, because of the shock and the repeated mantra of "don't have sex, sex is bad."
I'm now 18, and a college student, living on my own, and it took 3 years and a hell of a lot of distance for me to finally embrace my bisexuality and to FINALLY relax enough to have sex for myself, without feeling a shred of irrational guilt, safely and enjoyably... and would you look at that, I'm not dead or pregnant or riddled with STDS. I am, however, angry and upset that I spent 3 years of what should
have been & could
have been a much more fulfilling relationship constantly riddled with guilt and fear, unable to relax sexually and consequentially unable to relax and open up emotionally to my partner.
I repeat what SchrodingersCat said: DO NOT DO THIS TO YOUR CHILD. PLEASE. I hope it maybe helps to get the perspective of someone who was really affected by this in the recent past.