Our new favorite dating tip is something called “sperm competition”. A new study from Oakland University published in the Journal of Comparative Psychology found that couples tend to have more sex when the woman is surrounded by male friends and coworkers, aka “sperm competition.” The Frisky reports that since sperm has to fight to fertilize an egg, men replicate this competitive behavior in the dating world. The study followed 393 heterosexual couples whose female partners had varying degrees of relationships with male friends. The men reported on how many male friends and co-workers their partner seemed to have, how attractive these other men likely found their partner, and how many times they had sex in the past week. The more attractive they believed their partner to be, the more sex each couple had. Hot, jealousy-fueled sex.