Understanding autism in the light of sex/gender

Editorial Autism has long been described as a predominantly male condition, with a widely cited male:female ratio of 4 to 5:1 [1]. Over the past two decades, we have witnessed a trend towards a decreasing male-predominance [2]. Latest largescale population/community-based epidemiological studies converge to show a ratio of 2 to 3:1 [3]. The implications of this are important. Females with autism may have been underidentified and therefore underrepresented in the past, and consequently, the previous scientific and clinical literature likely may have provided a male-biased understanding of autism. However, a relative male-predominance remains a stable observation over time, which has led to fruitful aetiological and developmental investigations and theories [4-7,3]. For the field to move towards an integrated understanding of the whole autism spectrum, it is important that females are not overlooked, and their particular experiences are properly documented [8]. Sex and gender provide unique angles for understanding causal mechanisms in atypical human developmental conditions [9] and should be a central theme in the understanding to autism and its vast heterogeneity [3,10]. Note that the term ‘sex’ refers to ‘the biological and physiological characteristics that define men and women’ , and ‘gender’ refers to ‘the socially constructed roles, behaviors, activities, and attributes that a given society considers appropriate for men and women’ [11]. Since many human studies of autism focus on children, adolescents and adults, it is often difficult to empirically separate the effect of sex and gender, since gendered socialization begins at birth. Therefore, unless when we specifically refer to ‘sex’ or ‘gender’ separately, as defined here, we use the term ‘sex/gender’ to note the inevitable overlap between them [12]. Molecular Autism, since its launch in 2010, has published a range of research in relation to sex/gender and