So what STDs get transmitted that way? Hmmm?
Herpes is a very common infection. It is caused by two different but closely related viruses. The viruses are herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Both are easy to catch. They remain in the body for life and can produce symptoms that come and go.
Both forms of herpes can infect the oral area, the genital area, or both. When the infection is on or near the mouth, it is called oral herpes. Oral herpes is caused most often by HSV-1. When a herpes infection is on or near the sex organs, it is called genital herpes. Genital herpes is caused most often by HSV-2. Up to 8 out of 10 American adults have oral herpes. And about 1 out of 4 American adults have genital herpes. Millions of people do not know they have herpes because they never had, or noticed, the herpes symptoms.
Herpes is spread by touching, kissing, and sexual contact, including vaginal, anal, and oral sex. It can be passed from one partner to another and from one part of the body to another. Brief skin-to-skin contact is all that's needed to pass the virus. Because herpes may have no symptoms for years, sometimes it is very difficult to know who passed it to whom.
More info: Planned Parenthood
I figure if anyone has a vested interest in emphasizing the dangers of "unprotected" sex it's these guys.