"McCain had good reason to be flustered. The premise of the reporter's question is a myth. We couldn't find any data that show a disparity between health insurance companies that cover Viagra and those that cover birth control. The full range of contraceptives, in fact, are covered by more than 86 percent of private insurance plans written for employers."

http://www.factcheck.org/elections-2008/mccains_viagra_moment.html