Childhood innocence eventually becomes a thing of the past. If we’re lucky, it becomes fond memories and reason for nostalgic reflection when we’re adults or the need to keep that innocence alive in our children for as long as possible. Last week, my almost 10-year-old son asked me two innocence-ending questions. The first was about the existence of the tooth fairy. He doubted it and said he was pretty sure we put money under his pillow and took his tooth after he went to bed. Jonathan and I had already agreed to tell our kids the truth when they ask questions like that, so I told Drew the truth—that he…