Why do some women pursue relationships with men who are attractive, dominant, and charming but who do not want to be in relationships-the prototypical sexy cad? Previous research shows that women have an increased desire for such men when they are ovulating, but it is unclear why ovulating women would think it is wise to pursue men who may be unfaithful and could desert them. Using both college-age and community-based samples, in 3 studies we show that ovulating women perceive charismatic and physically attractive men, but not reliable and nice men, as more committed partners and more devoted future fathers. Ovulating women perceive that sexy cads would be good fathers to their own children but not to the children of other women. This ovulatory-induced perceptual shift is driven by women who experienced early onset of puberty. Taken together, the current research identifies a novel proximate reason why ovulating women pursue relationships with sexy cads, complementing existing research that identifies the ultimate, evolutionary reasons for this behavior.Keywords: evolutionary psychology, ovulation, mating, mate selection, fertilityIn 1939, when asked to comment on the prospects of his opponent the New York Giants, Brooklyn Dodgers manager Leo Durocher responded with "nice guys finish last" (Durocher & Linn, 1975). This aphorism is often used to describe young men's success at dating, with many women saying they want a nice guy but nevertheless dating men who are not-so-nice (McDaniel, 2005). Across cultures, many women believe that a good romantic partner is someone who is reliable, is dependable, and will make a good father (Buss, 1991;Buss et al., 1990). Yet, many women pursue and are heartbroken by men who are charismatic, adventurous, physically attractive, and hopelessly unreliable (Buss, 2003;Kruger, Fisher, & Jobling, 2003;Rhodes, Simmons, & Peters, 2005). Indeed, whereas popular dating guides for men teach bachelors how to be the "bad boy" women cannot resist (Louis & Copeland, 2007), dating guides for women implore them to steer clear of commitment-phobic men and instead choose the reliable "Mr. Good Enough" (Gottlieb, 2010). Why is it that, despite continuous warnings and recurring heartbreak, many women keep pursuing the wrong guy?In this article, we build on past research showing that women's desire for sexy, dominant, and charismatic men is related to their monthly ovulatory cycle (Gangestad, Simpson, Cousins, GarverApgar, & Christensen, 2004;. Although previous work has shown that women experience an increased attraction to such men when they are ovulating, it is unclear why ovulating women would think it is wise to pursue relationships with men who may be unfaithful and might desert them. In the current research, we examine a potential proximate psychological mechanism that may motivate women to believe it is a good idea to pursue men who are sexy, dominant, and charismatic, but who are also likely to be unreliable partners-the prototypical "sexy cad." We propose that ovulation might lead women to...