The relationship between AR polymorphisms and behavioral phenotypes remains to be elucidated, but some evidence suggests that a high number of CAG repeats is associated with cognitive aging (Yaffe et al., 2003), whereas a low number of repeats is associated with violence and aggressiveness, as well as depressive symptomatology and autism, in correlation with basal T levels (Jönsson et al., 2001; Seidman et al., 2001; Cheng et al., 2006; Rajender et al., 2008; Manuck et al., 2010). The gene discussed is AR; the disease is autism.