Sorry, guys: Mopping the kitchen may not help you get lucky in the bedroom.Men who do more household chores typically viewed as feminine — like cleaning, cooking and washing — have less sex than men who don't, according to a new study.The findings, published today (Jan. 30), in the February issue of the journal American Sociological Review, are correlational, so they can't say whether dishwashing actually makes men less sexy.But the trend jibes with other research showing that egalitarian marriages, though happier, are less likely to have that sexual frisson, said Pepper Schwartz, a sociologist at the University of Washington and the author of "The Normal Bar: The Surprising Secrets of Happy Couples and What They Reveal About Creating a New Normal in Your Relationship" (Harmony, February 2013.)"That companionable part of the relationship turns out not to be so sexy," Schwartz told LiveScience.Equal partners may be such good friends they don't need to use sex as a way to communicate with their partners, said Schwartz, who was not involved in the current study. However, another factor not related to housework could also explain the sex-frequency findings, according to another scientist not involved in the study.Married couplesThe findings are taken from a 20-year-old U.S. data set that surveyed more than 4,561 middle-age couples on a wide variety of measures, including sexual frequency and household chores.On average, women did 80 percent of daily chores such as cleaning the house, washing clothing and cooking food. Historically, women have done most of these "core" home tasks that have been perceived, traditionally, as women's work, said study co-author Sabino Kornrich, a sociologist at the Juan March Institute in Madrid.Men did about 55 percent of tasks, such as paying bills, doing yard work, and driving or maintaining the car, which don't need to be done on a daily basis.More egalitarian marriages tended to be happier overall. But men who did more of the traditionally feminine tasks had sex less often than those who didn't take on much ironing or cooking. Those who did none of the core tasks had sex about 1.5 times more a month compared with households where men did all of the daily chores. Overall, couples had sex a little more than once a week.The difference in sex couldn't be explained by women who were in traditional marriages feeling more obligated or intimidated into having sex, the analysis found.Sexual scriptsWhile society has made huge strides in valuing women's paid work, gendered scripts may linger at home, Kornrich said."What we do in the house is really strongly tied to how people think of themselves as men or women or as masculine or feminine."Flipping those scripts may slightly lower people's sexual attraction to their partner, he said. Another possibility is that couples with more similar roles may feel slightly less like opposites and more like siblings, he added.Outdated?But while the findings are interesting, they may not hold for a younger generation more comfortable with fluid definitions of gender, said Constance Gager, a sociologist at Montclair State University in New Jersey, who was not involved in the study."Gender roles around housework and child care have been slow to change, but I think it's naïve to think they haven't changed in the last 20 years," Gager said.Gager has looked at the same data set and found that when tasks aren't segregated into "male" or "female" chores, men who do more housework tend to have sex more often.Given that, it's difficult to conclude that female tasks actually make partners less attracted to each other, and more likely that some other, unexplained factor could explain the link, she said.