Anatomy Lesson

Gotta love it when kids ask those unanswerable questions. Today, during a visit to Barnes and Noble with Seth, he spotted a book cover bearing a photo of a skeleton half buried in the dirt.
He stared at it for close to a minute, then leaned into me and whispered, "Mom, do your testicles (not the word he actually used) have bones?"
"No," I answered, then asked the fateful question. "Why?"
He pointed to the skeleton's sacral bone. "Look," he said. "That's a bone."
"That's in the back," I explained, patting his tiny little tush. "Not the front. It's called the tailbone."
Seth stared at the book cover again. "No fair!" he exclaimed. "How come he get to have a tail?"