A despicable trait of religious people is that of indoctrinating children with their own beliefs.
Children are naturally trusting and will tend to believe what an adult tells them, particularly if that adult is a loved and trusted parent.
Believers are always keen to tell atheists that faith is a matter of personal choice, and that their choice should be respected.
In that case they should respect the personal choices of their children. They should ensure that their children are broadly educated about religions (and agnosticism and atheism), and then allow them to make their own choices when they have the knowledge and the maturity to do so.
Anything less is surely child abuse.