Because the worldwide spread of AIDS has had such a tragic effect on millions of people world-wide, a number of myths, urban legends, and conspiracy theories have arisen surrounding the disease.

• An urban legend, common in some parts of Africa, claims that having sexual intercourse with a virgin will cure AIDS. Doing so does not cure the infected person. Rather, it exposes the victim to the risk of HIV infection and likely leads to further spread of the disease. This myth has gained considerable notoriety, having been seen at the center of certain recent stories involving sexual abuse and child rape.

• A misconception holds that a single person, a French Canadian flight attendant, introduced HIV to North America. For information on this belief, see Patient Zero.

• A common myth that originated in the 1980s is that AIDS is a "gay plague". Variants of this myth include the misconception that only gays can get AIDS, and the incorrect perception that gays brought AIDS to the world, or to North America. During the early 1980s, the disease's disproportionate occurrence within the gay community led some Christian fundamentalists to brand AIDS the "gay plague", a device used by God to show his "displeasure" with homosexual behaviour. This view was based upon a traditional Biblical interpretation that homosexual activity is a sin. Conservative religious spokespersons such as Jerry Falwell touched off considerable controversy when they described AIDS as God's way of punishing homosexuals. Opponents pointed out that, if this were true, hemophilia would be a sin and God would love lesbians (who have a lower incidence of AIDS than either gay men or heterosexuals of either sex).

• There have been reports that blood-sucking insects transmit HIV. However, there is no evidence for this. There is therefore no need to fear catching HIV from a mosquito bite. When mosquitos bite a person, they don't inject the blood of a previous victim into the person they bite next. Mosquitos do, however, inject saliva into their victims, which may infect them with diseases such as dengue, malaria, yellow fever or West Nile, but not HIV.

• HIV and oral sex: in some circles it is commonly believed, incorrectly, that HIV cannot be transmitted orally. While it is agreed that oral sex is a very much lower risk activity than vaginal and anal sex it has been established that HIV can be transmitted through both insertive and receptive oral sex. An insidious danger of this myth is that it results in increased practice of unprotected oral sex. Even if the risk of infection is very small from a single encounter, it increases with frequency of activity. The perpetuation of the "oral sex is safe" myth probably is driven by the fact that people typically find oral sex far less pleasurable with a condom or dental dam, and consequently cognitive bias inclines people to believe it is safe. The perception is also affected by available information which is sometimes unclear: studies have reported different conclusions about the safety of oral sex. Nevertheless, the practice remains widespread, particularly amongst homosexual men, and there have been relatively few proven seroconversions as a result.

Perhaps some of these myths serve as a psychological mechanism for people to cope with the epidemic, or perhaps, in some cases, as a device to lay blame on someone for the epidemic.