The analysis of gender disaggregated data about the academic members show that the female presence significantly decreases passing from the category of junior/senior researchers to the highest level positions of associate and full professors, indicating the existence of the so called 'glass ceiling' or vertical gender segregation. This phenomenon is confirmed by the under-representation of women in decision-making positions, such as heads of departments or institutions, and members of executive boards. The low percentage of women in positions of power may have repercussions on decisions affecting the entry and the retention of women within the higher levels of the academic hierarchy. Moreover, it is likely to act as a deterrent to young women embarking on a scientific career and an obstacle to their progression to the first stages of academia. This phenomenon, which is common to all the academic fields, tends to be even more evident in IST/ICT fields due to the lower presence of women at all levels.