Once, at a smart wedding in Northamptonshire when I was about 30, someone handed me a newborn baby and my skin broke out in hot hives. In Brazil, I met a ten-year-old street kid. I fed him, let him sleep and shower in my hotel room, bought him clothes, and felt an overwhelming desire to protect and nurture him. I had never before felt such a forceful maternal instinct. These events were profoundly physical reactions, both shocking to me. Just around the time of my trip to Brazil, the ghost of my never-born came back to haunt me. I began...