Researchers have suggested that female strategies for sexual selection in humans include the promotion of sperm competition. Sperm competition entails the simultaneous presence of fertile sperm from at least two males in the female's reproductive organ competing for the opportunity to fertilise the ovum. Certain behaviour patterns near ovulation may enable such competition. In this paper, we describe relative preferences for female sexual fantasy types and explore the idea that these preferences may help us understand the settings and mechanisms that promote sperm competition, and discourage interfemale competition. To expand this exploration, we also examine whether preferences vary with respect to the menstrual cycle. Our preliminary findings indicate notable preferences among females for multiple male-partner fantasies over multiple female-partner fantasies or fantasies that include multiple male and female partners. This suggests that females find multipartner settings as arousing as males do, but the psychological mechanism relating to settings that include the presence of same sex competitors may differ from that of males. We also discovered some indications that the female preference for promoting sperm competition and avoiding interfemale competition is the highest and strongest near ovulation.