I bought my diaper bag when I was barely five months pregnant. It was the one everyone seemed to have, and it was on sale. I kept it in a closet with all its packing tissue untouched until the baby came. There would be times in my pregnancy when I would need some sort of large vessel to ferry goods from my Brooklyn apartment across the East River and several New York City blocks toward the Hudson, but the diaper bag never crossed my mind. It was a diaper bag. Not a computer bag. Not a sack lunch