Study published in Journal of Health Psychology, Vol. 7, No. 3, 329-343 (2002). DOI: 10.1177/135910530200700310. The abstract states, "Infant male circumcision continues despite growing questions about its medical justification. As usually performed without analgesia or anaesthetic, circumcision is observably painful. It is likely that genital cutting has physical, sexual and psychological consequences too. Some studies link involuntary male circumcision with a range of negative emotions and even post-traumatic stress disorder (PTSD). Some circumcised men have described their current feelings in the language of violation, torture, mutilation and sexual assault."
The authors conclude, "The body of empirical evidence reviewed here suggests that there is severe pain at the time of circumcision and shortly thereafter in unanaesthetised boys, as well as heightened pain sensitivity for some considerable period of time afterwards. Evidence has also started to accumulate that male circumcision may result in lifelong physical, sexual, and sometimes psychological harm as well. A variety of forces are converging from fields as diverse as psychology, medicine, law, medical ethics, and human rights, all questioning the advisability of circumcision"
Read the full text of Male Circumcision: Pain, Trauma and Psychosexual Sequelae.