Women's mate choice is not as straightforward as selecting a mate that displays all of her desired qualities. Often, potential mates will possess some qualities that are desirable and some that are not, so women must assess the relative costs and benefits of their potential partners' traits and 'trade off'. Women's mate choices will also be constrained by the context in which they are making them, resulting in conditional mate choices. Some of the conditions that may influence female mate choice include the woman's own perceived attractiveness, the woman's personal resources, mate copying and parasite stress.