When grocery shopping for my children, I often ask myself, “Is this cereal healthy?” or “Are these carrots organic?” But until recently, I never thought to ask, “Did a 12-year old pick these strawberries?” Child labor is usually portrayed as a problem in poor, distant countries. But hidden in America are hundreds of thousands of children who pick the fruits and vegetables that end up in our grocery stores. As a researcher for Human Rights Watch, I’ve spent much of the past year interviewing dozens of children around the country who work in agriculture, often under difficult and dangerous...