The advances of women's history have led to the necessity of studying the difference between sexes and the relations between men and women. However, the ambition of a systematically sex-oriented story meets several obstacles which all relate to the distortion between sexes in the society and the feminine and masculine representations which every one, either man or woman, uses albeit unconsciously. Distortions in the documents themselves impede this parity ambition. The history of young people is a good example of this. Girls, at first, remained the blind spot of the social sciences during the 50s and the 60s. A girl was hardly perceived as a “young worker”, as work remains the exclusive domain of men in ideology. Girls are forgotten as high school pupils despite the explosion of secondary education. Nonetheless, they are considered as “women” and supposed to share the same female—if not eternal—“values”as their mothers. When young people speak of themselves, like in the survey commissioned by the French Ministry of Youth and Sport in 1966, their statements suffer the same bias. Work is associated with masculine and children with feminine. Sources therefore prevent history from being perfectly equalitarian. However, a historian should not give up this objective as the sources' critique itself allows a more accurate understanding of the implicit masculine and feminine.