Our approach with our eldest son was to provide information on a need to know basis, an approach encouraged at the time. The advice was to let their questions be the guide and not to overwhelm them with too much information. Now the assumption seems to be that if they are asking questions they want to know more than they know how to ask, so while you have their attention keep talking until they tell you they have heard enough.
So, our son heard the facts of life doled out piece meal fashion, with time to ponder. But during a trip with my husband and two younger siblings to Southern California, our son suddenly became impatient and needed all the details. He pressed his dad for more complete answers as his dad navigated heavy traffic on Interstate Highway 405. With two younger kids listening in, and my husband driving an unfamiliar car on unfamiliar roads, it was not an optimum time to delve into this topic, so my husband handed our son the cell phone and told him to call me at home, where I had remained with the baby and toddler, and ask me his questions. I suggested to my son that we talk in person when he got home, which we did. I thought our discussion went well, he listened intently while nodding earnestly. Then he asked me in a concerned manner, "Does Dad know about all of this?"
My oldest daughter, on the other hand, never asked a single question about where the new babies in our house came from, and refused to discuss it when I brought it up. I bought her a lot of books and told her I would be happy to talk when she had questions. She did not have any questions. Ever.
The process has gone more smoothly since we started attending the seminars at Packard. The very best thing about the seminar is that the health educator is hilariously funny. Being self-conscious ties up a lot of brain cells. Humor is an extremely effective way of easing the self-consciousness that would otherwise prevent most of us from remembering a single fact from all the excellent material she presents.
The second thing I like is that she emphasizes to the preteens that the adults who accompanied them to the seminar really, really want puberty to go well for them, and are there to answer their questions and help and guide them. I appreciate that my kids hear that, even though I have a hard time telling them myself!