Men are more likely to regret not seizing the opportunity for quick and meaningless sex (quel surprise alors!), while women are more remorseful about actually jumping into bed for a one-night stand, according to new research out of UCLA. “For men, in evolutionary history, every missed opportunity to have sex with a new partner was potentially a missed reproductive opportunity—a costly loss from an evolutionary perspective,” says study author Martie Haselton, Ph.D. "But for women, reproduction required much more investment in each offspring, including nine months of pregnancy and potentially two additional years of breastfeeding. The consequences of casual sex were so much higher for women than for men, and this is likely to have shaped emotional reactions to sexual liaisons even today."
Bottom line: Wanting a casual encounter simply proves you’re human—but show your humanity by taking her feelings into account, too. Just be a good guy.