I am sure someone else had said it, but no one is born religious, you start out as an atheist and it is what happens afterwards that determines whether you stay one.

"Of key predictors of religious disbelief, witnessing fewer credible cultural cues of religious commitment was the most potent...*

https://journals.sagepub.com/doi/full/10.1177/1948550621994001

My parents would have said they were Christian if asked, but were not overtly religious, so outside scripture classes at school (in Australia) I had no real religious indoctrination. I remember having serious doubts about it all no later than 6th grade, and by the time I was an adult I stopped writing any religion on forms that asked for it.