became more acceptable as notable works and compilations, such as "Morality, Sexual Facts and Fantasies", by Dr Patricia Petersen, Alfred Kinsey's Kinsey Reports, Erotic Fantasies: A Study of the Sexual Imagination by Phyllis and Eberhard Kronhausen, and Nancy Friday's My Secret Garden, were published. Today, they are regarded as natural and positive elements of one's sexuality, and are often used to enhance sexual practices, both in normal settings and in therapy. Many Christians believe that the Bible prohibits sexual fantasies about people other than one's spouse in Matthew 5:28. Others believe that St Paul includes fantasy when he condemns works of the flesh such as "immorality" or "uncleanness". Despite the Western World's relatively lax attitudes towards sexual fantasy, many people elsewhere still feel shame and guilt about their fantasies. This may contribute to personal sexual dysfunction, and regularly leads to a decline in the quality of a couple's sex life. Guilt and jealousy While most people do not feel guilt or disgust about their sexual thoughts or fantasies, a substantial number do. In general, men and women are equally represented in samples of those who felt guilt about their fantasies. The most notable exception was found in a 1991 study that showed that women felt more guilt and disgust about their first sexual fantasies. In women, greater guilt about sex was associated with less frequent and less varied sexual fantasies, and in men, it was associated with less sexual arousal during fantasies. Women also reported more intense guilt than men; both sexes reported greater guilt if their arousal and orgasm depended on a fantasy. Studies have also been carried out to examine the direct connection between guilt and sexual fantasy, as opposed to sex and guilt. One study found that in a sample of 160 conservative Christians, 16% of men and women reported guilt after sexual fantasies, 5% were unhappy with themselves, and 45% felt that their fantasies were "morally flawed or unacceptable". Studies that examined guilt about sexual fantasy by age have unclear results—Knoth et al. (1998) and Ellis and Symons (1990) found that younger people tended to feel less guilt about their fantasies, whereas Mosher and White (1980) found the opposite. A 2006 study examined guilt and jealousy in American heterosexual married couples. It associated guilt with an individual's fantasy ("How guilty do you feel when you fantasize about...") and jealousy with the partner's fantasy ("How jealous do