I chased my two-year-old from under the bed, the air full of joyous laughter as she shrieked when I playfully caught her in my arms. Beside me my five-year-old son watched us play, joining in when I pinned his sister down. In the other bedroom, my three-month baby daughter was sleeping soundly on the bed, unaware of the playful mayhem in the other room. "I'm doing this for the good of my children," I reminded myself. "Lie down, sweetheart," I said kindly. She did what she was told. "What are you doing?" he asked in shock in his little-kid voice I loved so much. I never got to hear his response.