Preferences for voice pitch change across the cycle.  When seeking a short term mating partner, women may prefer a male with a low voice pitch, particularly during the fertile phase.  During the late follicular phase, it is common for women demonstrate a preference for mates with a masculine, deep voice.  Research has also been conducted on the attractiveness of the female voice throughout the cycle.  During their most fertile phase of the menstrual cycle, there is some evidence that female voices are rated as significantly more attractive.  This effect is not found with women on the birth control pill.