Women lose their desire for sex over time, but men don't, researchers at the University of Guelph have found.
In a study, published online in the Journal of Sex and Marital Therapy, researchers Sarah Murray and Robin Milhausen examined the survey responses of 170 undergraduate students between ages 18 and 25. The participants, men and women who had been in heterosexual relationships for between one month and nine years, were asked to rate their relationship and sexual satisfaction and their sexual desire, LiveScience.com reports.
While the participants said they were generally satisfied with their relationships and sex lives, women expressed lower levels of sexual desire as the duration of their relationships increased.
For each additional month that the female participants were in a relationship with the same partner, their sexual desire decreased by 0.02 on a scale called the Female Sexual Function Index, which ranges from 1.2 to 6.0, LiveScience.com says. That dip may seem small, but the researchers said male participants' sexual desire, by contrast, remained steady.
An important consideration is that the study examines young, university students, whose results may be quite different from older adults in long-term relationships. As LiveScience.com points out, younger women may report losing desire after the "honeymoon phase" of a relationship has worn off. Younger couples may have also not had experiences like going on romantic vacations, getting engaged or becoming comfortable with exploring sexual fantasies, which could boost sexual desire in longer-term relationships.
Moreover, the study relies on self-reporting, and the researchers caution that men may not report decreases in sexual desire due to gender norms.
Nevertheless, the findings indicate sexual desire could be affected by different factors, depending on one's gender. For women, for example, that could mean whether or not she feels "relaxed, playful and sexy," Ms. Murray told LiveScience.com.
The results also lend support to an evolutionary theory that men continuously have high sexual desire to produce more offspring, while women's desire decreases as they focus their attention on child-rearing.
Of course, advice abounds on how to reignite that spark.