Oral sex may increase risk of cancer (kissing too, possibly)

Seriously worrisome study.

A 2007 study in the New England Journal of Medicine found that younger people with head and neck cancers who tested positive for oral HPV infection were more likely to have had multiple vaginal and oral sex partners in their lifetime.

In the study, having six or more oral sex partners over a lifetime was associated with a 3.4 times higher risk for oropharyngeal cancer -- cancers of the base of the tongue, back of the throat or tonsils. Having 26 or more vaginal-sex partners tripled the risk.

And the association increased as the number of partners -- in either category -- increased.