The number of mouth cancer cases in Britain went above 6000 last year, driven partly by oral sex, new figures suggest.
The number of cases rose to 6,200 in the last decade, up from 4,400 in 2001. Two-thirds of the cases are in men.
The condition is often linked to smoking and excessive drinking.
But experts have said the dramatic increase is down to a virus called HPV (human papillomavirus) which can be spread during sex.
Richard Shaw, a Cancer Research UK expert in head and neck tumours, said patients with HPV-related oral cancers tend to be younger and less likely to smoke.