What even Leviticus failed to proscribe, medical research now looks set to ruin for all of us. Several recent international studies have provided evidence of a link between mouth cancer and one of the many unedifying strains of the human papilloma virus - a virus that can be spread by oral sex.
The latest study is by Kerstin Rosenquist at the Malmo University faculty of odontology in Sweden. The dentist and researcher found that 36% of the 132 individuals with mouth cancer she tested were carrying HPV, compared with 1% of her control group.
Her results back up the findings of a larger study last year by a team at Johns Hopkins University school of medicine. They found that among patients with mouth cancer who tested positive for HPV, the virus was more common in those who had had multiple sexual partners or oral sex. A French study found that patients with oral cancer and HPV were also more likely to be connoisseurs of cunnilingus and fellatio, reporting three times the rate of such activity as those without the virus.
Unlike the Johns Hopkins team, however, who deemed the risk uncovered by their research too low to warrant recommending that people change their behaviour, Rosenquist has said that people "should avoid oral sex".
Before oncologists and dental dam manufacturers are besieged by panicking hordes, a few facts should be borne in mind: namely, that the risk of contracting oral cancer via any means is low (about one in 10,000 people will develop the disease), and that by far the greatest risk factors remain oral fixations of another kind; smoking and heavy drinking.
Nevertheless, the studies were prompted largely by the increasing prevalence of the disease in young people, which could not be explained by decades of sucking down tobacco fumes and booze, with many researchers speculating that a link between oral sex, HPV transmission and the illness would be the most likely explanation for it.
So the best advice would seem to be to join with the organic food movement and not eat anything unless you are in possession of certified documentation as to its provenance.
