Scientists believe a virus spread through oral sex is behind the doubling in rates of throat and mouth cancer in young people over the last few decades.

Human papilloma virus (HPV), responsible for causing around 70 per cent of cervical cancers in women, is also believed by scientists to cause cancers of the mouth and throat in young men.

Such cancers, usually diagnosed in older men who drink or smoke, are now being detected in younger men.

The health scare has prompted doctors to call for boys to be vaccinated against HPV just like teenage girls to stop the disease.

Speaking at the American Association for the Advancement of Science conference in Washington, leading researcher into HPV Dr Maura Gillison said:

“I think the time has come to have a more through discussion about the potential benefits of HPV vaccines in boys,” Professor Gillison told the American Association for the Advancement of Science in Washington.

“When my patients ask whether they should vaccinate their sons I say ‘certainly’”

“The vaccine will protect them against genital warts and anal cancer and also as a potential byproduct of that it may protect them against oral cancer caused by HPV.”

More than 5,000 people a year contract oral cancer in Britain.

At present, only girls, usually aged around 12 and 13, are offered the vaccine against HPV to guard against the risk of cervical cancer.