The high disparities on educational levels and opportunities are important determinants of social and economic inequalities in Brazil, which makes their investigation extremely important. Educational inequality occurs early on individuals' educational career in Brazil. It is therefore essential to study the determinants of educational outcomes at the early stages of educational career, due to the potential to reduce inequalities in current and future generations. Data from the national representative PNAD surveys from 1977 to 1999 are used with the goal of answering whether the base of the educational distribution has become more meritocratic during the last decades. The determinants of years of schooling and school enrollment for 1963 and 1983 cohorts - pre and post demography transition - are investigated for all the country. Coefficients from multivariate analyses are utilized for simulations and decompositions, with the purpose to understand the role of social origin in determining educational opportunities. The results show that children from younger cohorts aren't penalized in terms of their educational outcomes, as are the ones from older cohorts because of their mothers' low levels of schooling. Educational inequalities due to intergenerational transmission of education have decreased. Nevertheless, the role of social origin in determining educational levels has persisted.