I think one of the big problems in the church today is that children from Christian households are falling away from their faith.
There are undoubtedly a number of reasons for this (lack of preparation for the arguments against Christianity that they'll hear in college is a big one), but I'd like to speculate about one reason I haven't heard explored, and it is this:
I think that every generation sets a new baseline for the following generation.
Let me give an example.
Let's say a man and woman have been involved in some bad behavior (take your pick), but they come to know Christ and begin following Him, living as good a life as they can, and then they marry and have children.
The problem is that while the parents remember how Christ saved them and how he set their lives straight, and while that is powerful for them, it's just ancient history to the children. The children don't see the change in their parents' lives; they simply experience having fairly nice parents and they tend to assume that this is normal and is no particular evidence of God. In fact, they will see that the parents do not always live up to their faith and may take that as evidence against Christianity.
And, of course, some parents are just plain awful, which simply makes the contrast between the parents' words and their professed faith even more damning.
So its a bad situation if you're a good parent and a worse situation if you're a rotten one.
I wish I had a simple answer for this. I don't, but two thoughts come to mind: be the best parent you can be, and ... pray.