Vaginal injuries are as common in voluntary sex as they are in rapes, a new study indicates.
The research carried out in Denmark casts doubt on the commonly held view that vaginal injuries are evidence that intercourse has been forced.
When police officers around the world investigate rape cases, the presence of lesions inside a woman's vagina is taken as an indicator of whether she has been assaulted.
Consensual: Danish research indicates that vaginal injuries are as common among women who have had voluntary sex as among rape victims
There have even been cases where men have been convicted of rape, which can carry up to a life sentence in the UK, based on vaginal injuries as the key evidence.
An in-depth study comparing rape victims with nursing students at the University of Southern Denmark reveals that vaginal injuries are just as likely to result from consensual sex as rape.
Birgitte Schmidt Astrup, a doctor and a PhD student at the university's Institute of Forensic Medicine, told ScienceNordic: 'The findings are extremely interesting.
'The nursing students experience just as frequent vaginal injuries as rape victims, and so these injuries cannot be used for much more than to establish that intercourse has taken place.'
She added that in cases of convictions based on evidence of vaginal injuries, there could now be discussions as to whether there have been miscarriages of justice.
The study looked at 110 nursing students in their early 20s and 39 rape victims from Centre for Rape Victims at Odense University Hospital, all who whom were examined less than 28 hours after sexual inercourse.
Results showed that vaginal injuries were found in 36 per cent of rape victims and in 34 per cent of the nursing students.
The nursing students' results were not affected by whether they had engaged in rough or gentle sex, or whether they had used condoms or sex toys.
The rape victims were more difficult to study in the same way, because they rarely remembered the details of the attacks and because they usually didn't keep track of the duration of the assault.
'Before I came up with some of these figures, the investigators were inclined to be take the case seriously when there were injuries and less seriously when there were no injuries'
Birgitte Schmidt Astrup, University of Southern Denmark
Dr Astrup's findings, published in the journal Forensic Science International, have already had an effect on the investigations by the Danish police.
'Before I came up with some of these figures, the investigators were inclined to be take the case seriously when there were injuries and less seriously when there were no injuries,' she told ScienceNordic.
However, she added that while the figures for injuries remained roughly the same for consensual sex as rape there could be an increased risk of sustaining multiple injuries during forced intercourse.
Rape victims' injuries may also be more severe.
The kinds of mucous membranes different women have in their vaginas may also have an effect on the injuries they sustain from rough sex.
For example, U.S. researchers have shown that white women sustain up to five times as many vaginal injuries as women from other races.
Read more: http://www.dailymail.co.uk/news/article-2123246/Voluntary-sex-lead-injuries-rape-new-study-shows.html#ixzz1qpWz8riD