A 2011 study that surveyed young adults about their emotional reactions after sexual encounters found that men reported more positive and fewer negative emotional reactions, and both men and women reported that the experience was largely more positive than negative. Women reported that condom use was associated with fewer positive and more negative emotional reactions, and for men condom use was associated with fewer negative emotional reactions. A 23-year study in a Human Sexuality class investigated gender differences in men and women's reactions to their first sexual experience. In the earlier years of the study, men reported more pleasure and greater anxiety than women, while women reported more feelings of guilt than men. Cohort studies carried out over 23 years found that in later years, women expressed greater pleasure and less guilt. The differences between emotional reactions among men and women decreased slightly during the 23 years. Such decreases in differences to first sexual intercourse may be a result of the increasing normality of premarital sex in America. An international online sex survey compared responses of residents of 37 countries against World Economic Forum figures for gender equality in those countries, finding that countries with high gender equality had respondents report more casual sex, a greater number of sex partners, younger ages for first sex, and greater tolerance of premarital sex.