  Despite the legislation in force in most countries and the discourse on
gender equality, the observed reality, still today, shows a clear picture of
inequality and restrictions for women, particularly when the issue is the
choice of a career and the subsequent promotions. In many professions, although
women represent the majority in the entrance to undergraduate courses, their
participation is dramatically reduced as the career progresses to the highest
levels. While the participation of men increases, that of women decreases as
the academic levels move towards the top ranks. This kind of evolution of two
groups in opposed directions is usually referred as the "scissors effect". This
effect with respect to sexes also occurs in the area of physics, both in Brazil
and in the rest of the world. But at what age does this effect begin? What is
its intensity in the different stages of women's lives? In this article we aim
to shed some light on these questions by analyzing data of the Brazilian
Olympiad of Physics and of fellowships for physicists in Brazil. We observe the
systematic occurrence of scissors effect throughout the full studied data,
ranging from the first years of participation in the Olympiads (13 years old)
to the highest stages of the scientific career.
