How so?
While female-to-male transmission is rare, it is a possibility and has been documented. Many factors figure into its prominence in the gay male community but it is not confined to gay males, intravenous drug users, or deviant sexual behaviors. Healthy males and females do act as agents of transmission to one another. One reason why so few cases of female to male transmission are documented is because it is in fact simpler to prevent transmission of the disease from a known infected female to her partner, when proper precautions are taken.