For decades, Brazil has presented itself as a colour-blind nation in which most citizens are, at least to some extent, racially mixed. But a controversial education law is encouraging black Brazilians to assert their own distinct identity. Federal public universities now have to comply with government quotas for black students, as well as others deemed to be at risk of discrimination. Yet, since the rules allow applicants to self-define their colour, there have been numerous alleged frauds, and some universities are now creating inspection boards to assess students based on whether they appear phenotypically black. On the political right, there's a backlash among those who say the quotas are divisive and even racist. While some people of mixed race complain that they are 'not black enough'. But many black Brazilians themselves say they finally have a reason to acknowledge their ethnicity in a country where privilege all too often belongs to those of European descent. For Crossing Continents, David Baker reports on an issue that is at the heart of what it means to be black in Brazil. Michael Gallagher producing.