There is a reason for that which is quite bluntly --- women can't screw a man up the butt, while some men, especially bisexuals, like to do women that way. I have no respect for anyone who supposedly fights this disease if they don't repeat over and over again that very simple bit of information to people. If you don't want AIDS, don't let anyone but a doctor stick anything up your butt. That is how 99% percent of sexual transmissions occur. With vaginal sex, the chance of a non STD infected (open sores etc.) woman getting AIDS from an AIDS infected man is incredibly small. The chances of a non-infected man getting AIDS from an AIDS infected women is nil.
None of this is new information. Michael Fumento (sp?) published a book called The Myth of Heterosexual Aids nearly 10 years ago that statistical demonstrated that hetro AIDS is a myth. He was virtually blacklisted for telling the truth. The AIDS establishment is a money and political power racket, and is responsible for many deaths because they have not allowed the facts to be presented.