whether their models are HIV positive, but assume that they are infected. For example, Hot Desert Knights (HDK) was one of the studios that initially operated on the assumption that all of their bareback models were HIV positive. However, in February 2008 HDK announced that it would begin testing its models for HIV and engage in a process of "sero-sorting", which match HIV-positive performers with other HIV-positive performers, and negative with negative. Critics suggest that sero-sorting may not prevent the development of a multi-strain HIV "superinfection". By contrast, BelAmi is one of the studios that claimed from the beginning to test their bareback models for HIV before allowing them to participate in condom-free scenes. A notice on the BelAmi website states: "all our performers are regularly tested for the presence of HIV or other communicable diseases." Health risks In addition to sexually transmitted infections, mechanical trauma are the same as in anal sex. Unprotected anal sex is a risk factor for formation of antisperm antibodies (ASA) in the recipient. In some people, ASA may cause autoimmune infertility. Antisperm antibodies can impair fertilization, negatively affect the implantation process, and impair growth and development of the embryo. See also Creampie (sexual act) Gay sexual practices Saddlebacking HIV superinfection References Further reading Race, K. (2010) “Engaging in a Culture of Barebacking: Gay Men and the Risk of HIV Prevention”. In M. Davis & C. Squire (eds.) HIV Treatment and Prevention Technologies in International Perspective. Basingstoke: Palgrave MacMillan Nicolas Sheon and Aaron Plant, "Protease Dis-Inhibitors? The Gay Bareback Phenomenon," managingdesire.org. With a long list of further references. Riding Bareback: A Qualitative Examination of the Subjective Meanings Attached to Condomless Sex by MSM, Bruce W. Whitehead, Journal of Sex Research (Feb 2006) Sharif Mowlabocus, Justin Harbottle and CHarlie Witzel, "What We Can't See? Understanding the Representations and Meanings of UAI [unprotected anal intercourse], Barebacking, and Semen Exchange in Gay Male Pornography", Journal of Homosexuality, vol. 61, no. 10, 2014, pp. 1462–1480. Anal eroticism Sexual acts Sexual slang HIV/AIDS LGBT slang