Sex outside marriage, and sex that occurs under out-of-the-norm circumstances, may increase the risk of penile fractures, said study researcher said Dr. Andrew Kramer, a urologist at the University of Maryland Medical Center.
The heightened risk appears to be due to the unconventional situations, and consequently, locations, surrounding sexual acts, the researchers said.
Men in the study who had suffered penis fractures commonly were having sex in unusual settings, including in restrooms or at work, when the injury occurred. The majority were having extramarital affairs.
In such atypical situations, sex may be rushed and involve unusual or awkward sexual positions, Kramer said.
"All these factors could make the man less able to protect his penis from an unexpected sudden downward thrust leading to the fracture," Kramer said.
Kramer studied 16 cases of penile fractures treated at the University of Maryland Hospital between 2004 and 2011.
Half of the patients were having extramarital affairs, the study found. Most were having sex in unusual places, including bathrooms, cars and elevators, reports LiveScience.
Only three patients were having sex with their own wives in their own bedrooms, Kramer said.
The study has been published online in the Journal of Sexual Medicine.