FWIW, my wifes dad brought up her and her siblings in atheistic environment. Mom was nuetral. She learned the gospel while singing in the musical Godspell and accepted Christ 4 years later at age 24. About 12 years after that her sister and her sisters children accepted Christ largely by the influence of my wife and 14 years later her mother accepted Christ.
All of them wish they knew about God's love earlier and wish their father had taught the about it.
I was raised as a strict Catholic, and then I became an atheist later. My husband was raised very closely involved with his Presbyterian Church, and now he's an agnostic. It seems that people often go their own route.
If you're religious, you ought to be happy to see families like ours raising our children in an atheist/agnostic environment. My sons will probably turn out to be priests. ;)