I'm not going to write specifically about sex, drugs, or body odor. My hope is that you realize there are a number of topics that have to be discussed with teens. Two main reasons these topics are not discussed are avoidance and procrastination. Avoiding the discussion happens because it's uncomfortable or there is a belief that your teenager will bring the topic up for conversation when they are ready. It's rare for a teen to proactively talk about these topics, so don't expect it. Procrastination, for the most part, is due to parents having a hard time acknowledging that their kids are growing up faster than desired. It could also have something to do with not knowing what to say to your teen or how to say it.
Whether it's avoidance or procrastination, either result in a reactive conversation instead of a proactive one. Reactive conversations are the norm for most families, and involve addressing a topic or issue after the fact. Common examples include telling your child not to hit after they have hit someone, or telling your teen to call when they are going to be late after you've nervously waited at the door for your teen because it's 30 minutes past curfew. A proactive conversation is getting ahead of the curve, having a talk before something has occurred. This is where the puberty, sex, and drug talks are important. I'm not saying parents should be clairvoyant and anticipate events before they occur, but there are inevitable events that will happen as your child grows into a teen and beyond. Try to anticipate these events by preparing yourself and your teen.
When I mention talking to kids about sex or drugs, sometimes parents are worried that by having the talk too early, their kids will get "ideas in their head" and become curious when they weren't before. I have two things to say about this. First, If you feel it’s too early, then it’s probably too late. It’s a very different world than even 5 years ago. For all the good that technology has brought, it has made all kinds of information easily accessible. Kids are learning and hearing about "adult" things at an earlier age. Whether we like it or not, that’s reality. Second and more importantly (for me), I have never talked or worked with a teen who said they experimented with drugs, alcohol or sex because their parents talked to them and they became curious. It just doesn't happen that way. So kindly excuse that rationale from your head.
If you have a teenager in your home, these talks are already past due. Again, this doesn't mean you have to go into all the details. You should have a good sense of where your child is in their understanding of these topics, so proceed accordingly. However you choose to talk to your teen, be respectful and open. If your child is more naive than same-aged peers, then simplify the talk. If your child has shown interest or asked complex questions, then go for a more in depth conversation.
Still not convinced that you should be the primary resource of information for your teen? Well then think of it this way: If you aren't talking to your child about sex or drugs (or body odor, for that matter), then they are probably learning about these things from their peers or the internet. Which would you prefer?
For teens that may be reading this, I'm sorry to put you in a potentially uncomfortable situation, I really am. I do it because I care about all of you. For parents, it would be great to always be the "cool" parent and your kids' best friend, but in many instances the parental duty is more important. Sometimes you have to be the "lame" parent that talks to your kids about potentially awkward issues. You can be the cool parent when your kids are in their 20s and they ask if they can move back into the house.