In order for someone else to see your son or daughter via their webcams, your son or daughter must be already using software which allows for use of the webcam over an internet connection. Some webcams even have to be turned on in order to work. What I'm saying here is no one can see your children via their webcams unless your children are allowing themselves to be seen. Sure, they could accidentally leave it on with the communication software running, I suppose, but not likely. If you think your son or daughter might be inclined to take their clothes off so as to be seen naked over their webcams, then yes, remove their cameras. Otherwise, make sure they understand the dangers of talking with strangers over the internet, and that having their webcams is a privilege which they should not abuse.

As for your initial question concerning whether or not a child can be a pedophile, the answer is no. Pedophiles are adults who are sexually attracted to prepubescent children; however, popular opinion also includes sexual attraction to adolescents who are younger than the legal age of sexual consent.