Not so very long ago, my daughter's passions included her Elmo doll, her art projects, and an unfortunate activity she referred to as "the buzz." With her arms wrapped tightly around the wobbly form of her baby brother, she would open her mouth as wide as possible and lick his head until he cried. I wondered if these two small creatures who shared my womb, albeit two years and eight months apart, would ever truly enjoy each other's company.