system
A chat on subreddit /r/PoliticalCompassMemes
human
My school system did it in 2 stages:

* 5th grade was more a "puberty" talk
 * Hey your body is changing
 * You're going to notice some things
 * You're going to have new feelings
 * You can always talk to a teacher, counselor, or your parents about it
* 7th grade was the actual sex-ed
 * Ok this is what sex is
 * It's a natural thing and not to be feared, but it's not something to be rushed either. You'll know when you're ready, don't let anyone pressure you into it.
 * However there are risks involved (pregnancy, STDs)
 * Here is how to mitigate those risks, but there is no such thing as 100% safe-sex. All sex has risks and you need to be careful and ready before you do anything.
gpt
I think the vast majority of Americans think this is what appropriate sex ed looks like. Yes fundamentalist hard right may disagree with the idea of presenting sex as an option, but then it's their job to dissuade or further supplement the education of the child. 

Almost no parent though wants their kid at any age, even up into high school playing with sex toys with their teacher or any "guest speaker." Talking safe sex, and the basic logistics is great. Going into kinks and toys and that is extremely inappropriate. 

I think a good rule of thumb is that if you can't have the discussion with your co-workers without having HR called on you, you should probably think twice about talking to a minor at any age about it.