By Gary Duffy,
BBC News, Rio de Janeiro
Many Brazilian universities have already adopted affirmative action policies
There are more people of African descent in Brazil than in any country outside the African continent itself, but the higher you go in Brazilian society the less evidence there appears to be of that reality.
Critics say part of the blame lies with a system which has often failed to provide equality of access to third-level education, though recent years have seen some improvements.
To try to address the problem, many Brazilian universities have adopted affirmative action policies or quotas to try to boost the number of black and mixed race students, or more generally those from poor backgrounds.
Gisele says the quotas system has given her a head-start
It is a controversial approach which some argue is necessary to end decades of inequality, while others fear it threatens to introduce racial tension in a society which has been largely free of such problems.
Gisele Alves lives in a poor neighbourhood in Nova Iguacu on the outskirts of Rio de Janeiro, and says she doubts she would have got to college without a helping hand from the state.
She is studying at the State University of Rio de Janeiro (UERJ), which was one of the first to adopt quotas.
"I thought I was going to finish school, find work in a little shop, get married and pregnant and that would be it. I didn't expect much more than that," she says.
"But with the system of quotas I started to think I could go to university. My parents couldn't pay privately - if I wanted to study it had to be at a public university."
Giselle got her place in part due to Rio's controversial quotas system which sets aside 20% of public university places for poor black and indigenous students, and the same number for students educated in the much criticised public school system.
Those parents who can afford it often opt to have their children educated in more expensive private schools, giving them a considerable advantage when it comes to highly competitive university entrance exams - especially for prestigious courses such as law and medicine.
Mr Bolsonaro says the quotas approach is a form of reverse discrimination
It is a process which works against poorer students - which in Brazil often means black or mixed race.
"When you consider the way things are in Brazil, you can see that poverty has a colour," says Lena Medeiros de Menezes, vice rector at the State University.
"It will take a long time for investment in primary and secondary education to bring about equality. How do I see quotas? It's a way to change things and change them rapidly."
But in Rio de Janeiro a question mark hangs over the quotas system after a legal challenge mounted by state congressman Flavio Bolsonaro.
He argues the approach is a form of reverse discrimination.
"What are you going to say to a teenager who goes to do a university entrance exam and gets a high mark, but doesn't get through, but another teenager has passed with a much lower mark because they have a dark skin?" he says.
"What would be the legacy of that for future generations?"
White or black?
Rio's Federal University (UFRJ) does not operate a system of quotas, though the issue has been widely debated.
Prof Paixao says black Brazilians are largely absent from key professions
Professor Marcelo Paixao, who lectures there, says it is clear that in Brazil those of African descent are largely absent from many key professions.
"Here the percentage of black people holding jobs - such as doctors, engineers, economists, lawyers - is very low," he says.
"When you have universities - principally the most prestigious ones which are the public ones - so closed to presence of the Afro-descendent population, this means these professions will also continue to be exclusive to a certain group of people for a very long time."
The debate in Brazil is further complicated because of the sometimes uncertain definition here of who is white, black or mixed race - official surveys let people classify themselves.
Hundreds of years of racial mixing means that many Brazilians regard themselves as neither black nor white but something in between, and recent surveys suggest some people have even changed their view of how they should be described.
Racial equality law
Some argue that quotas even partly based on race introduce a tension that never existed in Brazilian society in the way it has in the United States, while others say it simply recognises the obvious link between being poor and black.
"I think the main issue has to do with poverty and the bad quality of basic education," says Simon Schwartzman, senior researcher at the Institute of Studies of Work and Society in Rio de Janeiro.
"People who are poor don't have access to good education; they have more difficulty in having access, in particular to the more prestigious courses. It is a question of poverty not of race.
"There are good reasons to be against race quotas in Brazil - I don't think it makes any sense at all. For people who are poor and didn't have a good education, I think there is a good argument for that, provided you do it properly.
"You can not force a racial identity in a population where a large percentage of the population don't have a clear racial identity and don't want that. If you look at the population and ask people 'what is your race?' - many people won't know exactly what to answer.
"That is not to say that you don't have prejudice, that the fact that you are black you don't suffer, because you do. You should do specific things about that, but not to institute a kind of national policy based on race," Mr Schwartzman says.
For a future generation of students this complicated question has still to be finally resolved.
A long-debated law on racial equality only recently passed an important stage in congressional approval by avoiding controversial issues such as quotas.
It appears the final word may be left to the country's Supreme Court which is due to give its views on the matter in the year ahead.