The next time someone in the room sneezes, you might want to wonder what exactly is on their mind after researchers found evidence that in certain people sneezing can be triggered by sexual fantasy.

Dr Mahmood Bhutta, an ear, nose and throat specialist at the John Radcliffe Hospital in Oxford, launched the study after seeing a patient who suffered "uncontrollable" sneezing fits every time he had a sexual thought.

"We thought this unusual and performed a literature search of the topic," he wrote in the Journal of the Royal Society of Medicine. Together with colleague Dr Harold Maxwell, Dr Bhutta found that typing the words "sex", "sneeze" or "sneezing" into Google produced a surprising number of hits.

"Although internet reports do not give us an accurate incidence, our findings do suggest that it is much more common than recognised," wrote Dr Bhutta and Dr Maxwell.

Sneezing usually occurs in response to nasal irritation, triggering a reflex that expels air at speeds of over 90 miles an hour. Eyebrow plucking can also provoke sneezing by stimulating the trigeminal nerve, which produces sensations in the face.

But other more puzzling sneezing triggers are also known, said the researchers. One was the "photic sneeze reflex" – an apparently inherited sneezing reaction to sunlight, which affects almost a quarter of the population. More rare were cases of people from the same family sneezing after meals.

Dr Bhutta said he believed sneezing when thinking about sex probably ran in families too. He added: "I think this reflex demonstrates evolutionary relics in the wiring of a part of the nervous system, the autonomic nervous system... Sometimes the signals in this system get crossed, and I think this may be why some people sneeze when they think about sex."