I was a child, looking back now, I realise that they systematically stripped away our childhood innocence, we knew and heard things no 'worldly' child would have heard.
I also remember these talks and remember I was a bit troubled by them. I was thinking the same thing: worldly children didn't hear about such things. But then, I remember the pride that I had in the sexuality course in school where they talked about a few things I already knew about.
My mom was also very open on the subject.
Now that I'm an adult and dad myself, I look back at all this and think my mom did a great job. I also believe the watchtower did a fairly good job had I been older than 10 year old at the time. I mean, the way the approached the subject is fine by me, but gosh, why in the world would you need hearing about the details when your 5 years old?