A major concern in any HIV prevention tool that involves a permanent or irreversible side effect is providing the participant or consumer sufficient detailed information of the risks and side effects as well as benefits. In essence, the participant or consumer of the intervention must understand the costs and the benefits. And then the individual must be able to measure the two against one another in order to make an informed decision whether to partake.

Aidsmap has summarized a study on HIV vaccine trials that has valuable lessons for the ethical promotion of male circumcision. The summary is worth quoting:

    "The African-based HIV/AIDS Vaccines Ethics Group (HAVEG - part of the South African AIDS Vaccine Initiative) has been working to ensure that African vaccine trials are conducted ethically. One of the cornerstones of ethical research is “informed consent”: the participant’s right to freely choose whether to participate in a trial, based on full disclosure of the possible risks and benefits.

    "HAVEG has argued that “genuine consent means more than satisfying legal formalities (eg, signing consent forms)”, and that simple yes/no checklists may not be an adequate way to measure real understanding and genuine consent. This suspicion was confirmed by a recent study published in the December 15th edition of the Journal of Acquired Immune Deficiency Syndromes, in which HAVEG researchers used four different methods to measure how well participants understood various aspects of clinical trials. They found that assessments of “understanding” varied widely, depending on how they were measured, and that the simplest and most common measurements often overestimated the degree of understanding."

Male circumcision is fraught with cultural and sociological connotatations that go far beyond the mere medical understanding required in vaccine trials. Hence, myths are common. Moreover, the complications and risks are not fully understood or acknowledged even by the proponents. Therefore, providing a level of understanding sufficient to meet minimum informed consent standards in most cases is confusing and difficult. Such risks include, but are not limited to sexual dysfunction, post operative psychological trauma, scarring, an excess loss of skin, longterm loss of erectile function, and an irreversible loss of sensitivity and sensation. It is likely that many men would decline circumcision if they were told of these risks and in light of the better efficacy of the correct use of condoms.
http://www.nam.co.uk/en/news/6CD18701-3134-4109-9197-72E2989676B0.asp 

Reference
Lindegger G et al. Beyond the checklist: assessing understanding for HIV vaccine trial participation in South Africa. J Acquir Immune Defic Syndr. 43:560-566, 2006.