research on the perception of facial attractiveness suggests hormonal involvement in mate selection mechanisms. facial symmetry is one of four factors that is reliably associated with facial attractiveness, and there is evidence that people with symmetrical bodies and faces have adaptive characteristics (e.g., higher fertility, physical fitness, psychological health, and the potential to provide sexual pleasure). during the preovulatory phase of their menstrual cycle when conception is most likely, women's bodies are more symmetrical, and women show a visual preference for males with darker skin and more masculine facial features, as well as an olfactory preference for males with more symmetrical bodies. previous research has not examined whether women also show a preovulatory phase advantage in the visual detection of facial symmetry. in the present study, 45 women performed symmetry detection tests and rated the attractiveness of male faces that varied in symmetry level (low, normal, high, and perfect) at two of three phases in their menstrual cycle (menstrual, preovulatory, luteal). although there was no evidence to support the hypotheses that women are better at detecting, and show a preference for, symmetrical male faces during the preovulatory phase, there was evidence of an activational effect of hormones on facial symmetry detection and mate selection. the ability to detect facial symmetry was highest in the menstrual phase of the cycle and women rated all faces as sexier during the preovulatory phase, compared to the rest of the cycle. the findings were interpreted in the context of asymmetric hemispheric activation and evolutionary mate selection theory. also noteworthy was a dose-effect association between alcohol consumption and decreased visuoperceptual learning. the present endings provide strong support for a role of gonadal steroids in modulating both perceptual abilities and mate selection criteria.