Applying the feminist perspective, better known as gender mainstreaming, to justice, means assuming that the legal system, its rules and its applicators, are subject to a gender-conditioned bias. This bias prevents to consider the particularities of subjective and fundamental rights when the women are their titular. It prevents us understand the factual differences between men and women underlying the legal problems they face. It prevents to reach more appropriate material justice, taking into account the diverse effects that justice decisions can have on men and women. Such a bias, ubiquitous and implicit, is the one that seeks to overcome the gender perspective in the office of judging. This article raises how this overcoming is addressed in the field of action of the Spanish Constitutional Court.