It is pretty obvious that a religious upbringing affects the belief systems of children in quite a fundamental manner. If people were allowed to be religion-free until adulthood the results would be different as to how they perceive the world and the eventual religious or non-religious path that they would follow. Creating a belief system in a child is a very strong influence and a considerable traction, something that has been recognised by purveyors of religious and political dogmas throughout time.
https://www.huffingtonpost.com/kathl...b_5664805.html
"In our first study, we found that children’s judgments about characters in biblical narratives were strongly affected by their upbringing. Children who had had some form of religious education - via church, parochial school or both — generally judged the central character to be a real person. Children who did not have religious education — who did not go to church and went to a secular school — largely judged the central character to be fictional.
In a follow-up study, we obtained a similar pattern for what we might call quasi-biblical stories — stories that included miraculous events but not ones that children would read about in the Bible. For example, we told children a story about the parting of the mountains. Religious children were more likely than non-religious children to think that the main character was real."