Anytime you have to talk about the difficult subjects with kids, it's best to stick to the absolute basics, then encourage them to ask if they have any questions. Answer those questions honestly, and directly. Most times, a kid will be satisfied, even if you feel that they need to know more. Don't overload them, but never make them feel you're hiding something from them.
One of my friends was telling me about how she explained such difficult subjects as pregnancy and rape to her 8 year old. And she was astonished how her daughter went from asking "So how does the sperm get to the egg?" to "Oh. Can I go out and play now?"
I still remember when we talked about staying away from strangers in school, and the ensuing discussion at home. I wonder if things might have been different if those talks ever allowed the possibility that someone in the family could do the same things. I think that my own memories were pretty well blocked out at that time. As far as I'm aware, whatever abuse I might have had was over by the time this came up in school.
However, I was about 14, when I asked my mom, what was wrong. My great-uncle had just died, we were getting ready to go to the funeral, but my mom was acting strange, even for someone in the family dying. I had seen a few books on the coffee table about being surviving abuse in the previous weeks, so I put the pieces together already. I was glad she told me, but I have never felt as much hatred for a person, as I had that day in the church. Everyone was talking in glowing praises about a man, that my mom had told me "liked to touch little girls."
In the ensuing years, I've learned more about the extent of the sexual abuse within my family. I don't like the culture of silence about it. Everyone knows about it, but no one talks about it, except in hushed tones, in private. However, my aunt never let my (girl) cousin be alone with the great-uncle that abused my mom. At least actions WERE taken to protect other members of the family in my generation.
Unfortunately, no one was really aware of my grandfather. He, apparently, had a thing for little boys. Based upon my uncle's experiences, my brother's highly sexualized behavior, and my own dim and sketchy memories, I think we had another perp within the family, besides the great uncle.
So, to sum up, I agree with what Still12 had to say. It is your choice, Gords, since you know your kids best. Just give them the basics, and answer any questions they have in a way they can understand. They don't have to get the whole story in one sit-down. Best of luck to you Gords.
We're in this together.
Jeremy