Another example is the recommendation to take an aspirin daily. They are now finding out that it does little if anything to prevent a stroke or heart attack, and may have serious side effects, such as stomach bleeding, and may even cause strokes in some individuals.

http://en.wikipedia.org/wiki/Medical_analysis_of_circumcision#United_States

… Goldman (1999) discussed the possible trauma of circumcision on children and parents, anxieties over the circumcised state… and suggested a need on the part of circumcised doctors to find medical justifications for the procedure.[94] Boyle et al. (2002) state that circumcision may result in psychological harm, including post-traumatic stress disorder (PTSD), citing a study that shows an incidence rate of PTSD (measured according to DSM-IV) of almost 70% among Filipino boys subjected to ritual circumcision, and 51% among boys subjected to medical circumcision (with local anaesthetic).[95] Hirji et al. (2005) state that "Reports of [...] psychological trauma are not borne out in studies but remain as an anecdotal cause for concern."[96] The British Medical Association (2006) stated that the "medical harms or benefits have not been unequivocally proven," and that "[...] it is now widely accepted, including by the BMA, that this surgical procedure has medical and psychological risks."[13] Some organizations have formed support groups for men who are resentful about being circumcised.[1]