Same-sex cohabitation under the effects of quinpirole induces a conditioned socio-sexual partner preference in males, but not in female rats

► Cohabitation and the D2-type agonist quinpirole facilitate socio-sexual partner preference between male rats. ► This does not work on female rats. ► Males spend more time together, and display sexual behaviors and non-contact erections towards the preferred partner. ► The lack of intromissions and the steroid hormones may exert a negative effect on the formation of conditioned socio-sexual preference in females.