Irony for Non-Religious Parents

"Do you know last year, when I thought I was going to have a child, I'd decided to have it brought up a Catholic? I hadn't thought about religion before; I haven't since; but just at that time, when I was waiting for the birth, I thought, 'That's one thing I can give her. It doesn't seem to have done me much good, but my child shall have it.' It was odd, wanting to give something one had lost oneself" (Brideshead Revisited).

How many parents avoid a relationship with God and refuse to worship Him - until their first child is born? Why is it that we want for them what we have lost ourselves?