Are kids hardwired to eat boogers?

My always-ahead-of-the-curve Jack Henry has never eaten dirt, put rocks in his ears or stuffed peas up his nose. And he doesn't eat boogers. Or so I thought. His teacher told me that while he was sleeping soundly at nap time, he stuck his finger in his nose, pulled out a booger and ate it without waking up. Maybe my little genius is human after all.