Bad parenting is and always will be the greatest danger to a child. If you abuse your child, watch yourself.
There are other dangers to a child. It's not black and white though. Example: I frown upon the practice of converting a child into religion. Whenever a child tells me they're Christian or Muslim, I'm disappointed because he or she will probably never investigate the topic further. And if or when they do? They'd be older and feel like they've wasted many years of their life. Regardless of my own personal beliefs, whenever a child asks me if there's a God (I actually get asked this a lot), I tell them the truth: "I don't know." Afterwards, I encourage them to find their own answers without stepping on any religious beliefs.
I do, however, think we should teach the history of religion to our kids. We'd acknowledge what the specific religious belief is, where and when it was founded, what person or persons founded it, and what impact it's had on civilization. Jesus, Abraham, and Muhammad shouldn't be placed on a higher pedestal than Zeus, Odin, or Osiris. All receive equal research.
Unless you shelter your kid for the rest of their life, which makes you a bad parent in my eyes, your kid will learn about sex, drugs, and alcohol.
It's good to educate your child(ren) on sex. It's a very important subject. When you're child is mature enough to understand the subject, explain it to them. Please don't go evangelical on them by calling it a sin or making them feel guilty about it. That's really stupid. It's also very dangerous.
People like alcohol and drugs. When our kids grow up, some might choose to drink and smoke. If you catch your kid smoking or drinking, explain to them why it's wrong for them to do it. Getting pissed off and overreacting is an understandable response, but try to remember who and what they are: they're human beings, and human beings like to try new things. Curiosity isn't a bad thing. It can, however, be misplaced. People are very resourceful. Children are no different. If they want to try something new, they'll eventually succeed. There's no perfect plan here. We're not going to 'save' all of them. But most are smart enough to recognize it's wrong to do at such a young age and if you're a good parent, which is STILL very important, chances are they'll listen.
I'm appalled of the idea of giving a kid a whoopin' because they're spoiled rotten. I'd be more inclined to give their parents a whoopin'. Now there's nothing wrong with spanking. But there's a difference between spanking your kid and hitting them so hard they can't see straight. If you have to resort to hitting your kid or anybody for that matter because they're not doing what they're told or they disagree or are being rude, congratulations on being insecure. Find a better solution quickly, because there is a better way in handling little 'trouble makers'.
I know nasty kids who have really good parents. Some kids just can't help it. It's who they are. Hitting them makes 'em worse.
When they're mature enough, go ahead and explain what death is. It's better if they ask you what it is first. We're all going to die someday. It's important they know that. They're free to decide for themselves if life has meaning or not. The best thing you can do is be there for them. While it's true we die alone, we don't have to live alone.