We study gender differences in preferences for mate characteristics such as perceived (by the opposite sex) physical attractiveness and intelligence using data from the Columbia speed dating experiment. We have observed that the probability of a woman's positive speed dating decision rises with perceived male physical attractiveness, as well as their intelligence. The probability of a man's positive decision rises with perceived female physical attractiveness. However, the relationship between the probability of a man's positive speed dating decision and perceived female intelligence is non-monotonic. The optimal level of women's perceived intelligence can be found, and it depends on perceived female physical attractiveness. This optimal value rises with perceived female physical attractiveness. The results obtained suggest that virtually, in the women's view, male physical attractiveness can be effectively substituted for intelligence (equally male intelligence can be effectively substituted for physical attractiveness). By contrast, in men's view, for relatively high values of perceived female intelligence, female physical attractiveness cannot be substituted for intelligence. Research findings suggest that for relatively high values of perceived female intelligence this personal trait turns to be an economic bad.