Seventeen months after our first child—a boy—was born, along came a little girl. I was overjoyed at the thought of having a daughter, but I was also a bit uneasy because while I knew a few things about little boys, this was uncharted territory. We named her Sarah, and one of my privileges was rocking her to sleep so my wife could rest. I’m not sure why, but I started trying to sing her to sleep, and the song of choice was “You Are My Sunshine.” Whether holding her in my arms or standing above her in her crib, I…