The church is certainly a good source for teaching right from wrong but I don't believe it is the only possible source. A child can certainly be taught that harming another person is wrong without faith being a source for the lesson.
As far as Christianity being the correct religion, I can't say that I agree with you. Although I was baptized as a Christian, in my fifty-one years I have seen too many atrocities perpetrated by so called Christians, all in the name of morality.
Actually, IMO that is why Christianity is losing favor in this nation. Anyone who claims to be strongly religious and moral and then performs acts that show themselves to be hypocrites damages the perception of Christianity as a whole. I guess I have just seen too much hypocrisy to continue to believe.
Second, right and wrong and truth must come from God. They cannot come from anywhere else. My personal opinion really isn't worth more than yours. How can we tell between us? We must call on something higher.
Why should a child refrain from hurting others? Because his fellow man is made in the image of God and has inherent dignity because of that. We are God's highest creation, and He has forbidden us from destroying each other.
Without that we might as well regard each other as a bunch of animals, and after all we kill and eat animals. So I really have no source for my morality or the dignity of man with the God of the Bible.