People will lie about their sexual behavior to match perceived cultural expectations about how men or women should act, U.S. researchers say. Study author Terri Fisher, a professor of psychology at The Ohio State University's Mansfield campus, and colleagues said while people would lie about sex, they wouldn't distort other gender-related behaviors. "There is something unique about sexuality that led people to care more about matching the stereotypes for their gender," Fisher said in a statement. "Sexuality seemed to be the one area where people felt some concern if they didn't meet the stereotypes of a typical man or a typical woman." The study involved 293 college students ages 18-25. The students completed a questionnaire that asked how often they engaged in 124 different behaviors typical of either males -- such as wearing dirty clothes -- or females lying about their weight. Some filled out the questionnaire while they were attached to what they were told was a working polygraph machine or lie detector, which in reality was not working. Men reported more typical-male behaviors and women reported more typical-female behaviors, regardless of whether they were attached to the lie detector or not. The one exception was sexual behavior, Fisher said. The study, published in the journal Sex Roles, found when it came to sex, men wanted to be seen as "real men." They reported more sexual partners when they weren't hooked up to the lie detector than when they were, while women reported fewer partners when they were not hooked up to the lie detector than when they were. "Men and women had different answers about their sexual behavior when they thought they had to be truthful," Fisher said.