As a result of the epidemic of sexually transmitted disease in Europe in the 16th cent., efforts were begun to control prostitution. Brothels were closed throughout Western and Central Europe during parts of the 16th cent., and stricter punishment was meted out to those engaged in the trade. When these measures proved unsuccessful in stopping prostitution, many cities instituted even stricter controls. Berlin required medical inspection in 1700; Paris began to register its prostitutes in 1785. In Great Britain legislation to control the spread of sexually transmitted disease was embodied in a series of Contagious Diseases Prevention Acts (1864, 1866, and 1869) requiring periodic medical examination of all prostitutes in military and naval districts and the detention of all those found to be infected. Having failed to control the diseases, the acts were repealed in 1886. In 1898 the Vagrancy Act prohibited males from living on the earnings of prostitutes.
During late 19th cent. efforts were made to control the international traffic in women for the purpose of prostitution. Cooperation on an international scale to stamp out such traffic began in 1899 with a congress in London. This was followed by other conferences in Amsterdam (1901), London (1902), and Paris (1904), which resulted in an international agreement providing for a specific agency in each nation to cooperate in the suppression of the international traffic in women for the purpose of prostitution. In 1919 the League of Nations appointed an official body to gather all facts pertaining to the trafficking of prostitutes, and in 1921 a conference held at Geneva and attended by 34 countries established the Committee on the Traffic in Women and Children (the work of the committee was assumed by the United Nations in 1946). In 1949 a convention for the suppression of prostitution was adopted by the UN General Assembly.
In the United States, where prostitution was widespread, it was thought to be closely connected with other crimes. No major effort to stamp out prostitution appeared until about the end of the 19th cent. In 1910 the Mann Act, or White Slave Traffic Act, was passed through the efforts of James Robert Mann; it forbade under severe penalty the interstate and international transportation of women for immoral purposes. By 1915 nearly all the states had passed laws regarding the keeping of brothels or profiting in other ways from the earnings of prostitutes. Nevertheless, during World War I there was a great increase in prostitution, accompanied by an increase in sexually transmitted disease. In 1941 Congress, spurred by reports of widespread prostitution near military bases and a rise in sexually transmitted disease, passed the May Act; the law made it a federal offense to practice prostitution in areas designated by the secretaries of the army and the navy. On a local basis all states except Nevada now have legislation that makes it a crime to operate a house of prostitution. Most states have laws against all forms of prostitution, although they often exempt from prosecution the customers of prostitution. Among the many agencies in the United States and elsewhere that have worked for the suppression of prostitution are the Society for the Prevention of Crime, organized in 1877; the Committee of Fourteen (1905); the National Vigilance Association; and the American Social Hygiene Association.