If attractiveness judgments reflect biologically important reproductive criteria, men should base judgments of potential partners on objective physical criteria more than do women; homosexuals and heterosexuals of the same sex should perceive attractiveness in the same terms, regardless of the sex-object choice. To test this theory, photographs of men and women (20 each) were presented to members of four subject groups, solicited on an opportunistic basis. Subjects were asked to rank the sets of photographs separately on the dimensions of physical attractiveness and general social attractiveness. We found some sex differences across sexual orientation. There was less variation among men than women (heterosexual and homosexual) in evaluating "good looks" of sex objects. Heterosexual and homosexual men ranked younger sex objects higher than older ones on "good looks." Heterosexual but not homosexual women ranked older sex objects higher. Sex had little effect on "social attractiveness" rankings, nor did putative age. These findings are interpreted as generally consistent with the existence of average sex differences in evaluative mechanisms that reflect different reproductive interests.