According to the extreme male brain theory of autism (Baron-Cohen, 2002), autistic traits would be extreme manifestations of typical male behaviours. The Auyeung et al. (2009) paper establishes a link between autistic traits and higher fetal testosterone (fT) levels in typically developing children. We argue that the construct behind this relationship needs further investigation. First, the link between fT levels and sexually dimorphic traits, that are for example, associated with empathizing and systemizing, is controversial. Likewise, describing autistic behaviours as being extreme male-like is debatable. The cerebral hemisphere laterality pattern of individuals with autism also seems to differ from the pattern typically observed in males. Moreover, the parallel that should exist, according to the fT theory, between individuals with autism and individuals with congenital adrenal hyperplasia (CAH), because of their high fT levels, is unclear. The theory implying fT levels in autism fails to account for a big part of autism, and the link between fT and normal 'autistic traits' hardly demonstrates the causal link between fT and autism.