We just dropped off our twenty-year-old son at the airport. He is so, well, twenty. After raising two boys to manhood, I know that Kahlil Gibran was probably right: Our children are only on loan to us. I had heard it, but I didn’t have a clue of what that meant. When they were little, I fooled myself into thinking they were mine. But now I’m not so sure they ever were. Yes, they pretty much did what they were told—most of the time— because they didn’t know any better. However, those times didn’t last. And the boys often made...