Study published in International Journal of Epidemiology, April 2011. doi: 10.1093/ije/dyr104

Background One-third of the world’s men are circumcised, but little is known about possible sexual consequences of male circumcision. In Denmark (∼5% circumcised), we examined associations of male circumcision with a range of sexual measures in both sexes.
  
Results . . . circumcised men reported more partners and were more likely to report frequent orgasm difficulties after adjustment for potential confounding factors, and women with circumcised spouses more often reported incomplete sexual needs fulfilment and frequent sexual function difficulties overall, notably orgasm difficulties and dyspareunia.
  
Conclusions Circumcision was associated with frequent orgasm difficulties in Danish men and with a range of frequent sexual difficulties in women, notably orgasm difficulties, dyspareunia and a sense of incomplete sexual needs fulfilment.