Reasons for opposition to pornography include religious objections and feminist concerns (for specific sectors of feminism), as well as alleged harmful effects, such as pornography addiction. Pornography addiction is not a condition recognized by the DSM-5, or the ICD-11. Anti-pornography movements have allied disparate social activists in opposition to pornography, from social conservatives to harm reduction advocates. The definition of "pornography" varies between countries and movements, and many make distinctions between pornography, which they oppose, and erotica, which they consider acceptable. Sometimes opposition will deem certain forms of pornography more or less harmful, while others draw no such distinctions. A 2018 Gallup survey reported that 43% of U.S. adults believe that pornography is "morally acceptable", a 7% increase from 2017. From 1975 to 2012, the gender gap in pornography opposition has widened, with women remaining more opposed to pornography than men, and men's opposition has declined faster. Religious views on pornography Most world religions have positions in opposition to pornography from a variety of rationales, including concerns about modesty, human dignity, chastity and other virtues. There are numerous verses in the Bible which are cited as condemning pornography or adultery, notably for Christians, Matthew 5:28 in the Sermon on the Mount which states "that anyone who looks at a woman lustfully has already committed adultery with her in his heart." The Catechism of the Catholic Church explicitly condemns pornography because it "offends against chastity" and "does grave injury to the dignity of its participants" since "each one becomes an object of base pleasure and illicit profit for others". Islam also forbids adultery, and various verses of the Quran have been cited as condemning pornography, including Quran 24:31 which tells men to "restrain their eyes" from looking sexually at women.