Source here on Yahoo front page
LONDON (Reuters) - Although the risk is small and it is more likely to result from heavy drinking and smoking, scientists have uncovered evidence that oral sex can cause mouth cancer
Researchers had suspected that a sexually transmitted infection that is linked to cervical cancer could also be associated with tumors in the mouth. Now a study by researchers working for the International Agency for Research on Cancer (IARC) in Lyon, France seems to have confirmed it.
"Oral sex can lead to oral tumors," New Scientist magazine said Wednesday, referring to the latest research.
.... please don't show this to my GF!!!!