The transfer of faith from parents to children is not automatic. Anyone familiar with the gardening analogy will understand that the roses don’t just happen; weeds happen. Puritan William Gurnall describes the need for parents to tend the garden of their children’s minds with the transfer of the faith:
This is the difference between religion and atheism; religion does not grow without planting, but will die even where it is planted without watering. Atheism, irreligion, and profaneness are weeds that will grow without setting, but they will not die without plucking up.
Parenting our children in the faith is hard work. God equips us for the task.