There's a biological reason for that, new research suggests.
It's likely that this shift in sexual preferences during ovulation is an evolutionary holdover for humans, scientists report.
In the past
In the past, highly masculine characteristics in men likely indicated high genetic quality, and mating with them increased women's odds of having children who would survive and reproduce.
Prof Martie Haselton, senior author of the study and a professor of psychology at the University of California, Los Angeles (UCLA), explains:
"Ancestral women would have benefitted reproductively from selecting partners with characteristics indicating that they'd be good co-parents, such as being kind, as well as characteristics indicating that they possessed high genetic quality, such as having masculine faces and bodies."
"Women could have had the best of both worlds – securing paternal investment from a long-term mate and high-genetic quality from affair partners – but only if those affairs were timed at a point of high fertility within the cycle, and probably only if their affairs remained undiscovered.
Women experience preference shifts
"Women sometimes get a bad rap for being fickle, but the changes they experience are not arbitrary. Women experience intricately patterned preference shifts even though they might not serve any function in the present," Haselton, said.
Sexual preferences increase offspring's chance of survival
The researchers noted that female mammals have shifting sexual preferences and behaviours meant to improve their offspring's chances of survival.
"Until the past decade, we all accepted this notion that human female sexuality was radically different from sexuality in all of these other animal species – that, unlike other species, human female sexuality was somehow walled off from reproductive hormones," Haselton said. "Then a set of studies emerged that challenged conventional wisdom."