Thanks to playing Mary in her preschool's Christmas pageant and eagerly anticipating the birth of a cousin, the four-year-old is totally engrossed by the question of babies.
"When I was a baby," she asked her brother, "how old were you, S1?"
"I was three," he replied promptly.
"And when you were a baby," she continued, "how old was I?"
"You were not born yet," I started to say when S1 interjected with his answer, "negative three!"