Prof.:
I often think of this but can't find it - some time back you produced one of your habitually well-sourced and detailed posts about the dismal retention rates of religion in those brought up in one and the next-to-neglible rates of adoption of religion in those not brought up in one.
It impressed me then and has stuck in the brain box since then, but I can't find it. If you can repost the stats, or provide a link to the post in question, I'll be in your debt.
The seminal work was done by David Voas, although his findings have been corroborated by a number of other surveys including the British Social Attitudes survey.
He looked at children who were brought up in a household with 2 religious parents, one religious and one non religious or 2 non religious parents. He then assessed whether or not the children chose to be religious when they became adults.
He found that only 50% of children brought up in a religious household with 2 religious parents chose to remain religious as adults.
When there was only one religious parent, and one non religious, that figure dropped to 25%.
By contrast a child brought up in a household with 2 non religious parents had a 97% likelihood of choosing to be non religious when they reached adulthood.
So despite all that effort on the part of religious parents to bring their children up as religious (with the associate cultural community trying to achieve the same - faith schools, Sunday schooling, all those 'initiation' ceremonies) they have only a 50:50 chance of being successful in transferring their religiosity.
Yet the non religious parents - most of whom will do nothing active to try to get their children to be non religious - have nigh on 100% likelihood of passing on their non religiosity.