Autistic features in girls from a psychiatric sample are strongly associated with a low 2D:4D ratio.

Autistic features such as deficits in social interactions and communication have been associated with a low 2D:4D ratio in normal children.This study assessed this association in a large sample of children with a variety of psychiatric disorders (n = 35 girls and n = 147 boys). Autistic features were assessed with a highly valid and reliable measure (Autism Diagnostic Observation Schedule-Generic). Correlations between the 2D:4D ratio and autistic features were computed separately for boys and girls. Some small negative correlations (r = -0.17 and r = -0.19) were found in the right hand for boys; however, particularly in girls, large negative correlations (r = -0.51 to r = -0.64) were found in the left hand. A low 2D:4D ratio in girls was highly predictive of the presence of autistic features. Thus, a low ratio could possibly be used as a diagnostic predictor in clinical practice.