All children are born Atheist, without the knowledge of God or whatsoever. There is an advantage to our survival to be receptive to thinking in a way that makes it easy for us to believe in religion. If that is true, you'd think that young children would think of supernatural explanations before natural ones. But a recent study disproves this idea or at least shows that it's too simplistic. When asked to explain why something might have happened, 8 year olds are most likely to suggest natural explanations.
The older you are, the more likely you will suggest something supernatural. So the tendency to think in supernatural terms is learned from your culture. There might be a pre-disposition to accept supernatural explanations but they don't come without being taught. Children do seem to be born Atheists or at least not believers in the supernatural. Whereas Christians will argue that when you pray for your child and talk to them about God during your pregnancy then the child is born Christian.
During my time limited research I did trying to understand the concept, I came across the common belief by Christians that a person chooses to be Atheist for only one reason, if they were to believe in a God they would need to follow that God’s moral code as he/ she has revealed to humanity. The number of Atheist, whether “strong” or weak” as I met this two distinct words during my research, I spoke to actually get offended by this assumption by Christian, they believe that they see no evidence for such being(s) and see no indicators that such being(s) exist. They cannot accept the existence of God, just as the average Christian cannot accept the existence of Thor, Venus, Baal, and other goddesses and gods of antiquity.
Growing up in a Christian + Religion family had been rather a bit confusing, with a father who was a priest but still believed in the existence of ancestors, whereas a lot of Christians whom most of them are my friends, believe that ancestors do not exist, only Jesus and God the Father. I grew up to understand that most Christians I know refuse to see or seek reason to why Atheists believe there is no God, all they know is that God do exist and he lives through them. That is why they are called Christians, meaning Christ like.
Then the matter of religion which I personally believe Christianity falls under the brought spectrum or umbrella of religion, like the belief in Buddha, God(s), Allah, ancestors inter alia. Religion is all about beliefs, ethical codes, rituals, liturgy and general community or society beliefs.
From my stand of view, each parent or family raise their children in what they believe is the truth and what they think will be morally accepted, not by the world or community but by them. While growing up one makes the choice on what they want to believe in based on their observations.
While Atheists say they believe in no God and supernatural powers, Christians say there is a God who made heaven and earth and there is a life after death. I think we all fall under religion, one way or the other, whether Christian or Atheist. There is something that each and every one believe, Atheist “BELIEVE” there is no God and there is no life after death and Christians “BELIEVE” there is a God and there is life after death.
At the end of the day, the operative word is “Believe”. Religion is “believing” in something, it does not necessarily mean you are a Christian or an Atheist, it simply means there is something that you believe in with every beat of your heart.