Do you know what blows your boyfriend's mind in bed? Do you think you and your girlfriend are titillated by the same things?

A new study suggests that your sexual satisfaction depends more on the latter question than the former.

In previous research on relationships and happiness, the age-old question of “Do opposites attract?” has garnered a chorus of dissenting answers, depending on which characteristics are studied. Findings show that similarity of values predicts relationship satisfaction more consistently than similarity of personality. A 2008 meta-analysis showed that within established relationships, a perception of similarity is more important than actual similarity.

Psychologists at the University of Rochester examined this topic from a more risqué point of view. Their research, published online this month in Personality and Social Psychology Bulletin, surveyed 304 heterosexual couples, who ranged in relationship length from one month to 34 years.

"Imagine that Jack enjoys giving oral sex and that Jill enjoys receiving oral sex. Their preferences are not similar, but they complement each other’s in ways that their idiosyncratic desires can be met."

Each individual completed a questionnaire on their own sexual preferences, what their partners like, and what they think their partners think they like—a boudoir-themedNewlywed Game, if you will.

Then, researchers used two ways to measure sexual compatibility: similarity and complementarity. Similarity is based on how often the individuals in a couple select similar answers on a statement like “When it comes to sex, I enjoy hearing my partner talk dirty.”

Complementarity is when the partners' sexual preferences complement each other. The authors write, “Imagine that Jack enjoys giving oral sex ... and that Jill enjoys receiving oral sex.... Their preferences are not similar, but they complement each other’s in ways that their idiosyncratic desires can be met.”

While it might sound obvious, this is the first study to examine sexual complementarity. And the results showed that the Jacks and Jills certainly benefited from having complementary desires—more so than from having similar desires—by reporting greater sexual satisfaction.

The study also showed that couples tended to overestimate their sexual compatibility, which jives with previous studies that show couples tend to idealize their partner or overestimate similarities in other traits. Participants also overestimated the accuracy at which their partner would know their own preferences.

This divorce from reality, though, seems to be working in favor of happily unaware couples. Being overly confident about sexual compatibility was a “robust” indicator of both partners' sexual satisfaction.

Lastly, the study confirmed a previous finding that women whose partners know what they like are more sexually satisfied than women whose partners are clueless. The same is not true of men. Apparently, whether or not a woman knows her man’s preferences does not predict his sexual satisfaction. Researchers suggest that since it’s more difficult for women to reach orgasm than men, Jack’s knowledge of Jill’s turn-ons is especially important to their sexual chemistry.