Safe Sex


Estimated per act risk for acquisition

of HIV by exposure route (US only) [80] Exposure Route Estimated infections
per 10,000 exposures
to an infected source Blood Transfusion 9,000[81] Childbirth (to child) 2,500[61] Needle-sharing injection drug use 67[82] Percutaneous needle stick 30[83] Receptive anal intercourse* 50[84][85] Insertive anal intercourse* 6.5[84][85] Receptive penile-vaginal intercourse* 10[84][85][86] Insertive penile-vaginal intercourse* 5[84][85] Receptive oral intercourse 1[85] Insertive oral intercourse 0.5[85] * assuming no condom use
§ source refers to oral intercourse
performed on a man

So the reason to use a condom is to prevent insemination, and the spread of the much more prevalent and virulent STDs like chlamydia and gonorrhea.  I guess HIV is scarier because it’s less curable, and often leads to AIDS, which is usually fatal.