Oral sex is fuelling an 'epidemic' of throat cancers, experts claim.
It comes after figures published by the American Cancer Society say the number of cases of cancer caused by oral sex is up 1.3% a year in women and 2.8% in men.
This is because the acts can lead to an HPV infection at the back of the throat or near the tonsil.
While in most cases the infections will go away on their own, some will go on to develop into throat cancer.
Scientists at NYU Langone estimate that as much as 70% of throat cancer cases are caused by HPV infections.
In the UK, head and neck cancers combined are responsible for more than 12,000 cases and 4,000 deaths per year.
Dr Mehanna said people with multiple oral sex partners have an up to nine-fold increased risk of throat cancer.
Writing in The Conversation, Dr Mehanna said: "Over the past two decades, there has been a rapid increase in throat cancer in the west, to the extent that some have called it an epidemic.
"This has been due to a large rise in a specific type of throat cancer called oropharyngeal cancer.
"HPV is sexually transmitted. For oropharyngeal cancer, the main risk factor is the number of lifetime sexual partners, especially oral sex.
"Those with six or more lifetime oral-sex partners are 8.5 times more likely to develop oropharyngeal cancer than those who do not practice oral sex."
While there is a vaccine for HPV, figures in the US show only 54% of Americans have received it — far below the 80 percent figure believed to be a threshold for population safety.
Actor Michael Douglas has claimed performing oral sex on women triggered his throat cancer.
The Hollywood star, 68, previously blamed years of boozing and smoking for causing the illness.
But he has now said his strain was due to human papillomavirus – a sexually transmitted disease.
He said in an interview: “Without wanting to get too specific, this particular cancer is caused by HPV, which actually comes about from cunnilingus.”
The dad-of-two said he feared the stress of seeing son Cameron jailed for drugs offences triggered his cancer.
But he added: “But yeah, it’s a sexually transmitted disease that causes cancer. And if you have it, cunnilingus is also the best cure.”
