Two-year-old Franklin Delano Roosevelt sits primly on a stool, his white skirt spread smoothly over his lap, his hands clasping a hat trimmed with a feather. Shoulder-length hair and patent leather ...

Dressed in pink from head to toe and surrounded by her many pink possessions, four-year-old Jeeyoo strikes a pose in her Seoul, South Korea, bedroom for a 2007 photograph. Also in Seoul, six-year-old ...

Walk into any children's clothing store and you'll see it immediately: the great divide. Blues, greens, reds, and blacks flood the boys' section, while pink and purple dominate the girls' area. But is ...