No, really?
I honestly don't understand what people mean when they say that they're letting their kids decide for themselves. It doesn't matter whether it's religion, politics or anything else, kids are going to be influenced by their parents' perspectives, and no matter how hard a parent may try to present various alternatives to their kids and to do so in an objective way, his or her own biases are going to come through, probably when he is least aware of it.
Looking at something other than religion, for instance... I love the bumper sticker I see from time to time which says, "Nobody is born a bigot." I was raised in an atmosphere where my parents' and grandparents' strong opposition to racism was evident to me when I was literally six or eight years old. I can't recall
ever having heard them sit down and tell me that judging a person as good or bad, smart or stupid, or trustworthy or devious based on the color of his or her skin, but you can be sure I knew it was wrong. The same holds true with regards to a belief in God, in my opinion. If parents believe in God, they are going to convey that belief to their kids whether they make a point of doing so or not. If parents think a belief in God is totally irrational, that's going to rub off, too. It just is. So why do atheists insist on saying that theists' children are "brainwashed" but that their own children are not? It's simply not how it works.