I grew up in a home where my mother and father, both fallen-away Christians, wanted to let my sister and I “decide our own beliefs.”
The idea, of course, is that we are blank slates and my parents would not indoctrinate me into a particular religion, thus letting me collect data and inputs over time and eventually grow up and choose my own beliefs or worldview. I can see how someone would think this makes sense.
But in fact my sister and I both became agnostics, mirroring the (un)belief system of our parents. This was no accident, because it’s impossible to rear your child in a vacuum. Whether you like it or not, you are teaching them things about the world, existence, and faith (through your actions, the things you say (and don’t say), etc.).
They bought us books on evolution that claimed humans evolved from single-celled organisms; we never once said a prayer in our home thanking “someone” for the many blessings we had; we only went to church for a short time, and that was at the Unitarian Universalist one where people believed all kinds of contradictory things. In short, the guidance we were given supported an atheistic materialism worldview and argued against a Christian one.
It is not surprising then that my sister and I both became agnostics (though in truth I was militantly atheistic, seeking to convince Christian friends that God did not exist). Did we choose this? Yes, but the unbelief of our parents was an instrumental influence in our decision, as it is with any child.
There is no escaping influencing your child. The only question is: what will you influence them to believe?
This great responsibility is all the more reason to yourself delve into philosophy so as to understand the right use of reason, allowing you to penetrate into the truths of existence and ultimately supporting the assent of faith in Jesus Christ and His Church. Along these lines, I would highly recommend Dr. Feser’s book The Last Superstition, which refutes the New Atheists via the right use of reason. Reason is on the side of Christianity.
You can only give what you yourself possess: form yourself in the truth that you may pass it on to your children. Do not be fooled when an atheist claims you are “indoctrinating” your children into your belief system. You are teaching them the objective truth of existence. They are seeking to do the same, only their beliefs are false and so they pass on errors to their children.
Whether Christians or atheists, we have the responsibility as parents to teach our children how to reason cogently. If we instruct them in this invaluable skill, we can be hopeful that they will be able to discover the truth.