The other moms are forcing me to write about this, otherwise I never would, and if I were you, I would pay attention to what they are writing about instead of what I am because I have no idea what I am talking about on this one. In fact, I am headed over there to take notes right now.
We are mostly of the "less is more" attitude when it comes to discussing these things. "Just the facts, ma'am" pretty much sums up our curriculum in the, er, human development area.
See? I don't even like to refer to it!
Since we seem to have a baby every couple of years, and now that we live in the country and our kids have witnessed dogs doing... what they do, and baby goats being born, we do have questions that come up every now and then, and we try to answer those as succinctly and matter of factly as possible.
And then I run into the bathroom and hyperventilate. I'M KIDDING! Mostly.
Our children know and understand that God intends for husbands and wives to only ever love one another and keep themselves for each other. They also know, from reading the Proverbs, that it can be a temptation to disregard this plan, and doing that is sinful and foolish.
Beyond that, and teaching the simple biological changes that come with puberty, I am not an advocate of OVER education. You can see more of my thoughts about this trend here  and how we address the dangers of promiscuous behavior here .
We haven't used a curriculum or any specific book, so I don't have any to recommend to you. See? I told you I would be no help here!