Women are underrepresented in science and their participation decreases as the career progresses, an international phe-nomenon clearly displayed in a scissors graph. This decrease is usually attributed to maternity, lower number of publicationsand less ability of receiving grants. Here we present a comprehensive study of the Brazilian science and technology system,covering 8,877,626 people, and analyzing the participation of women from the undergraduate to ministerial levels. The studyused different data-bases to develop relevant indicators of the participation of women, some of them over a period of 15 years.Our results suggest that the decrease of women as the career advances is due to a combination of barriers which need to befaced and eliminated to promote equity for a better science.