intended frankly as a manual of group-sex." Health As with all sexual activity, the relative risks of group sex depend on the specific activities engaged in, although having a large number of sexual partners increases one's risk of exposure to sexually transmitted infections (STIs). From the mid-1980s there was active lobbying against gay bathhouses, blaming them for the spread of STIs, in particular HIV, and this forced closures in some jurisdictions, particularly in the United States. Sociologist Stephen O. Murray, writes that, "there was never any evidence presented that going to bathhouses was a risk-factor for contracting AIDS." In other countries, fears about the spread of STIs have prompted the closing of bathhouses—with their private rooms—in favour of sex clubs, in which all sexual activity takes place in the open, and can be observed by monitors whose job it is to enforce safer sex practices. Proponents point out that venues where group sex takes place often provide condoms, dental dams, latex gloves, lubricants and other items for safer sex. Bathhouses in particular are a major source of safer sex information—they provide pamphlets and post safer sex posters prominently (often on the walls of each room as well as in the common areas), provide free condoms and lubricants, and often require patrons to affirm that they will only have safer sex on the premises. Prevalence In a 2015 US survey, a significantly larger percentage of men than women responded that they had any lifetime experience of a threesome (17.8 vs 10.3) or group sex (11.5 vs 6.3). Law The Sexual Offences Act 1967 decriminalized homosexual acts between two men over 21 years of age in private in England and Wales; however, the privacy restrictions of the Act meant a third person could not participate in the sex or even be present, as well as that the two men could not have sex in a hotel. These restrictions were overturned in the European Court of Human Rights in 2000. Section 20A of the Immorality Act, 1957, commonly known as the "men at a party" clause, was a South African law that criminalized all sexual acts between men that occurred in the presence of a third person. The section was enacted by the Immorality Amendment Act, 1969 and remained in force until it was found to be unconstitutional in 1998 by the Constitutional Court in the case of National Coalition for Gay and