Discriminating between consensual intercourse and sexual assault: Genital-anal injury pattern in females

Background: Assessment of genital-anal (GA) injuries following sexual assault promotes health and assists prosecutors to build a case. The pattern of injuries may help differentiate between consensual and nonconsensual intercourse, bolster the survivors' credibility, and increase prosecutions in sexual assault cases. Objectives: To identify the constellation of G-A injury-related characteristics that most effectively discriminated between consensual sexual intercourse and sexual assault in females when controlling for intercourse-related variables. Methods: We employed a comparative study with two groups: a prospective cohort group with consensual participants and a group derived from an existing sexual assault registry. In the prospective cohort, we performed a sexual assault forensic examination at baseline and following consensual sexual intercourse with females >21 years. We compared their injury patterns to the injury records of females >21 years who were sexual assaulted. Results: We enrolled a sample of 834 females: 528 consensual (63.3%) participants and 306 non-consensual (36.7%) registry cases. After controlling for race/ethnicity, age, and time between intercourse and examination, logistic regression analyses showed that the presence of an external genital tear increased the odds of nonconsensual intercourse more than two times (adjusted odds ratio [AOR] = 2.70, 95% CI = 1.28-5.56). Logistic regression analyses also showed that the odds of non-consensual sexual intercourse were significantly greater with a lower prevalence and frequency of external and internal genital redness, lack of condom use and lubrication, and presence of anal penetration. Latent class analysis identified high and low G-A injury prevalence subgroups among both consensual and non-consensual samples. One subset of results emerged that may be indicative of non-consensual as compared to consensual intercourse: a higher prevalence of external genital and anal tears. Conclusion: External genital tears occurred more frequently in the non-consensual sample and increased the odds of non-consensual intercourse more than two times. Anal tears, swelling, and ecchymosis and anal penetration were markers for non-consensual intercourse and should increase suspicion for lack of consent.

Automated summary

The presence of external genital tears significantly increased the odds of non-consensual intercourse, while anal tears, swelling, ecchymosis, and anal penetration were markers for non-consensual intercourse. Overall, these findings support the importance of assessing genital-anal injuries in cases of sexual assault to differentiate between consensual and non-consensual intercourse.