Sex Ed! What should we really be teaching our kids?

I was eavesdropping on my 5 year old playing house with his cousin, had a laugh at the role play but it does beg some questions. The girl was mommy and my son daddy, she spent the whole game complaining about how much house work she had, and without listening to a word she said my son asked her to pour him a drink. Is this what we teaching our kids what marriage is about?
We were discussing at book club (the source of all knowledge) when is the appropriate time to start teaching our kids about the birds and the bees. 3 was suggested starting age of basic anatomy getting more detailed with the years. Research I have done suggests always being prepared as they will ask at the most random times. This got me thinking what I was taught, I can remember a book with cartoon sperm, a talk and a bad PACT skit/play at school, and my mother saying that if cant do it in public you shouldn't be doing it. Did this really prepare me, I am not sure.
I read a blog written by a dad wishing his daughter has great sex in her life, not locking her behind a chastity belt. Not promoting promiscuity, but yes, sex is awesome.
We spend so much time complaining that our husbands should be more intuitive, knowing when we need a glass of champagne, when to be left alone, when to be hugged, when to put the kids in the car and disappear for an hour or two. We expect alot from them in the bedroom as well, they need to know when we want to be cuddled, when we want to be thrown on the bed for a good Rogering and when to sleep in the other room with very little definate input from us. Reading some articles in mens magazines by men commenting on why Christian got women dripping like a perculator, majority concluded that women secretly like to be dominated or that women are materialistic. I wanted to shout at these articles saying no no no. It was signing off each email differently, rubbing soothing lotion on her bruised ass, and other such acts. Treat her like the most important person in the universe and you can do whatever you want to her in the bedroom.
So... How do I teach this concept to my boys? Is it possible to teach this, or is it nature? I have started with old fashioned chivalry. What should we be teaching our daughters? How do we help them create a world that just a little better?