I suspect what happens in the UK, may not be the case in the rest of the world.


"Although HIV is often perceived to be a 'gay' problem, infections acquired through heterosexual sex account for the largest number of HIV diagnoses in the UK. The majority of people who acquired HIV heterosexually were infected overseas but only became aware of their status after being tested in the UK. In terms of HIV infections actually occurring within the UK, gay men (and other men who have sex with men) accounted for two thirds of new cases."
Source

http://www.avert.org/aids-uk.htm

Since infection through oral sex is low, I suspect that is not a significant cause. Homosexual women may also be a low contribution to the stats. I suspect bisexual folks would be a factor.