It might have emancipated women from the drudgery of the 'Missionary Position', but it seems that men are paying a painful price for revolution in the bedroom.

"Woman on top" is the most dangerous sex position, according to a new scientific study.

Scientists have found that the position, dubbed "cowgirl", is responsible for half of all penile fractures in the bedroom.

The research also revealed that the "doggy-style" position, with women on all fours, is behind 29 per cent of afflictions.

In contrast, the traditional "man on top" is responsible for just 21 per cent.

Doctors and academics looked at patients attending three A&E units with suspected "penile fractures" over a 13 year period.

Half of them reported hearing a crack before experiencing pain, with some also suffering swelling.

Their average age was 34 and some of the men waited up to six hours before seeking medical help.

The research concluded: "Our study supports the fact that sexual intercourse with 'woman on top' is the potentially riskiest sexual position related to penile fracture.

"Our hypothesis is that when woman is on top she usually controls the movement with her entire body weight landing on the erect penis, not being able to interrupt it when the penis suffers a wrong way penetration, because the harm is usually minor in woman with no pain but major in the penis.

"On the contrary, when the man is controlling the movement, he has better chances of stopping the penetration energy in response to the pain related to the penis harm, minimizing it."

The study found that 44 men had attended hospital, with 42 having "the condition confirmed after clinical, radiological and surgical evaluation".
Of these, 28 were injured in heterosexual romps, four during homosexual intercourse, six as a result of "penis manipulation" and four in circumstances which were "unclear".

The study, published in the Advances in Urology journal, reads: "Half of patients (50 per cent) presented with the classical triad of an audible crack followed by pain.

"The presentation time of patients to the hospital after penile fracture ranged from 0.5 to 6 hours."

"Penile fracture is a relatively uncommon clinical condition that frequently causes fear and embarrassment for the patient, hypothetically resulting in delayed search for medical assistance, which can lead to impairment of sexual and voiding functions,” said the authors.

"Considering that most studies are retrospective and based on patients records information regarding the social dynamics surrounding penile fracture is scarce in the literature, mainly potentially risky sexual positions."

The scientists, who looked at three hospitals in Campinas, a city of three million people in Brazil, used hospital records and in some cases interviewed the patients.