Obsessive-compulsive disorder (OCD) displays sex differences in age of onset, progression, and symptomatology, however, the genetic basis of sex differences in OCD has not yet been comprehensively explored (Flament et al. 1990; Swedo et al. 1989; Bellodi et al. 1992; Boileau 2011). Epidemiological studies indicate a worldwide lifetime prevalence of OCD between 1 and 3% (Kessler et al. 2005; Ruscio et al. 2010; Torres and Lima 2005; Weissman et al. 1994) and while boys comprise approximately two thirds of the childhood cases of OCD, typically defined as onset before age 15 (Flament et al. 1990; Swedo et al. 1989; Bellodi et al. 1992; Boileau 2011), females predominate the late-onset cases of OCD. In addition to demonstrating a later age of onset, females with OCD have higher rates of precipitating events which include pregnancy and childbirth (Lochner et al. 2004/3; Gerald Nestadt, Grados, and Samuels 2010). Compared to females, males with OCD report more religious, sexual, and symmetry symptoms, more alcohol dependence, and lower rates of marriage and employment. Females with OCD are more likely to be married, report more sexual
