There have been 46 women in the Senate in the entire history of our country

20 are still in the Senate. 34 of them are still alive. The first woman to serve did so less than 100 years ago. http://www.senate.gov/artandhistory/history/common/briefing/women_senators.htm

Given that, I don't think people taking into account gender when making their voting decisions is sexist when it benefits a female candidate. For me the fact I am voting for the first woman President is certainly a bonus. Again, over three quarters of the women who were in the Senate, for even a day, are still alive. People are alive who were sentient when the first woman was named to the Senate.