Oral sex dramatically increases the risk of head and cancers, a new study has claimed.
The disease has traditionally been considered to be one that affects smokers and heavy drinkers in later life.

But over recent years, as cases have been rising, it has been linked with the common human papillomavirus (HPV).

It is believed oral sex may be the main way HPV - more usually associated with cervical cancer - ends up in the mouth.

The group of viruses affect the skin and moist membranes which line the body, including the anus, cervix and mouth and throat.

HPV-16 is a well-known cause of oropharyngeal tumours - those which affect the middle part of the throat including the soft palate, the base of the tongue and the tonsils.

While HPV does not directly trigger cancer, it causes changes in the cells it has infected (for example, in the throat or cervix), and these cells can then become cancerous.

Men are twice as likely to get oropharyngeal cancer as women, according to NHS choices, because performing cunnilingus is more risky than fellatio.

It is the 11th most common cancer worldwide, according to World Health Organisation figures.
Worldwide almost half-a-million patients a year will be diagnosed with oral and oropharyngeal cancer.

More than two thirds of cases are diagnosed in advanced stages where the cancer has already spread to regional lymph nodes or beyond, the global oral cancer forum reports.
Approximately 150,000 patients die each year and many more suffer from the complications of treatment.

While girls in the UK aged 12-13 are offered a vaccination to help protect them against types of HPV that can cause cervical cancer, there is no immunisation programme for boys.

An official recommendation on whether to offer the HPV vaccine to all adolescent boys is expected in early 2017.