American women in the fertile stage of their menstrual cycle speak with voices that are more attractive than those of women who are passing through their infertile stage.
Nathan Pipitone and Gordon Gallup at the University at Albany, part of the State University of New York, recorded the voices of 51 women at four points in their menstrual cycles. Voice samples were then played to 34 male and 32 female participants who rated the attractiveness of the voices.
Participants of both genders scored the voices as more attractive when the women were fertile, suggesting that although women do not obviously advertise their fertility, they unwittingly send subtle cues. Perhaps unsurprisingly, such variation was absent in women taking the contraceptive pill.