Evidence suggests that heterosexual men find ovulating women more visually attractive than women taking oral birth control or au natural women during less fertile menstrual phases. But does ovulation also announce itself with auditory advertisements as well? Yet again, study results lean toward the affirmative. Vocal recordings of women across their menstrual cycle tend to demonstrate tonal deterioration as menstruation approaches [source: Barnes and Latman]. Clinicians have notes cases of premenstrual voice problems among classically trained female singers, for instance [source: Barnes and Latman]. Off-stage, men listening to audio samples of female voices rated the clips captured during women's periods as the least appealing, compared to the sweeter sounds heard from more fertile menstrual phases [source: Pipitone and Gallup Jr.].
Researchers suspect varying levels of hormones and their effect on vocal tissue are responsible for such vocal inconsistencies [source: Pipitone and Gallup Jr.]. For women taking oral contraceptives that deliver a stable dose of estrogen and other hormones, that issue may not affect them. Indeed, one study concluded that oral contraceptives may improve vocal stability over time [source: Amir and Kishon-Rabin]. That said, scientists haven't determined whether that difference portends real-world impacts aside from possibly improved karaoke performances, care of estrogen.