"Almost 24% of all relationships had some violence, and half (49.7%) of those were reciprocally violent. In nonreciprocally violent relationships, were the perpetrators in than 70% of the cases. Reciprocity was associated with more frequent violence among women (adjusted odds ratio [AOR]=2.3; 95% confidence interval [CI]=1.9, 2.8), but not men (AOR=1.26; 95% CI=0.9, 1.7). Regarding injury, men were more likely to inflict injury than were women (AOR=1.3; 95% CI=1.1, 1.5), and reciprocal intimate partner violence was associated with greater injury than was nonreciprocal intimate partner violence regardless of the gender of the perpetrator (AOR=4.4; 95% CI=3.6, 5.5)."
The peer reviewed publication can be found here in the American Public Health Association: http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2005.079020
Screenshot from PUBMED: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1854883/
Harvard Article: http://www.health.harvard.edu/newsletter_article/In_Brief_Domestic_violence_Not_always_one_sided