Religious indoctrination of children is nothing short of brainwashing
If I had a nickel for every time I have uttered that phrase. . .well, I say it a lot. It's frustrating how so few people understand what I mean.
Children are impressionable. If parents teach their children something when they're very young, it will stick. Look at Santa Clause: How many young children in America do you think are convinced that Santa exists?
The same goes for religion. Parents, for some strange reason, are allowed to teach their children that one religion is better than all others, and raise them with it. So many American children believe in a god simply because their parents do, and because their parents sent them to Sunday School, or Hebrew School, or whatever. When a three year old is brought to church and told that god loves him/her, he/she is going to get sucked in.
For example, I have a theist friend who said he started going to church at a young age. When I questioned him, he went on about his god's powers, and how much his god loves him. At one point he even admitted omnipotence is an illogical idea, but that doesn't matter if his god is omnipotent.
Similarly, I have a friend who told me she started going to church around the age of three, and is a rather firm Catholic. She says that indoctrination of kids is not brainwashing. . . "it's religion." Obviously, faith suspends normal social rules.
Sadly, it's going to be a looooong time before anyone in power recognizes that it is a bad thing for parents to raise their kids with a religion. The only thing children can do about this is spread the word themselves.