Dorothy Roberts (left) is the George A. Weiss university professor of law & sociology at the University of Pennsylvania. Her parents, Robert and Iris, married in the 1950s. Cris Crisman/Simon & Schuster; Dorothy Roberts hide caption toggle caption Cris Crisman/Simon & Schuster; Dorothy Roberts Almost a decade after her father’s death, legal scholar Dorothy Roberts still had 25 boxes of his research that she had yet to sort through. When she moved from Chicago to Philadelphia, she brought the boxes — and finally opened them. Roberts’ father, Robert Roberts, was a white anthropologist who spent his career at Roosevelt University in Chicago. The boxes contained transcripts of nearly 500 interviews he had conducted with interracial couples across the city, including interviews with couples who were married in the late 1800s, all the way to couples who are married in the 1960s. “They were absolutely fascinating,” Roberts says of the transcripts. “I learned so much about the racial caste system in Chicago, the Color Line, the Black Belt.” Initially, Roberts saw the project as a chance …