FYI, some forms of female circumcision are less drastic than male circumcisions. From the World Health Organization's page on female circumcision:
Type IV — All other harmful procedures to the female genitalia for non-medical purposes, for example: pricking, piercing, incising, scraping and cauterization.
Some of of the other types outlined by the WHO are also less drastic than you describe.
There is in fact evidence that female circumcision reduces the risk of HIV infection in women (Stallings and Karugendo 2005), but given Western cultural preferences it is unlikely that there will ever be clinical trials to test and confirm the possibility.
It's the same sort of factors that are being used as reasons to increase rates of male circumcision in Africa.