WASHINGTON -- When Patty Murray first won election to the U.S. Senate in November 1992, women were a rarity, holding only two seats. The Washington state Democrat arrived for her new job to discover there was no bathroom for women near the Senate chamber.

“They had to build one when six of us arrived in ’93,” said Murray, laughing at the thought.

Today 17 of the 100 senators are women. And after leading a two-year recruiting campaign to elect more women, Murray predicts that 2013 will be a historic year, bringing a record high number of female senators to Capitol Hill.

One thing’s certain: Five closely contested races involving women whom Murray recruited to run – in Massachusetts, North Dakota, Wisconsin, Nevada and Hawaii – will go a long way in deciding which party controls the Senate next year.

Overall, party leaders are backing 11 Democratic women as candidates this year, the most in history. That includes six incumbents who are considered shoo-ins or leading in the polls. A 12th Democratic woman is running in Maine, but without the endorsement of the Democratic Senatorial Campaign Committee.

On the Republican side, six women are running this year, in Nebraska, New Mexico, Hawaii, Connecticut and the Democratic strongholds of California and New York. But two longtime incumbents – Olympia Snowe of Maine and Kay Bailey Hutchison of Texas – are retiring.

For Murray, the Senate’s most powerful woman and its fourth-ranked Democratic leader, the personal stakes are high. She took the job as head of the DSCC two years ago, when others turned down the job, amid predictions that the Republican Party would have a healthy advantage in winning elections this year.

“There was no one else who wanted it,” Murray said in an interview.

The conventional wisdom two years ago was that the GOP would have a great chance of winning control of the Senate. But that seems to have disappeared now. Of the 33 seats up for grabs this year, 23 are held by Democrats, compared with only 10 for Republicans.

Jennifer Duffy, who analyzes Senate races for the Cook Political Report, said there’s a 60 percent to 65 percent chance that Democrats – who now have 53 of the 100 seats – will keep control of the Senate in 2013.

“Given where they started, things do look more promising,” Duffy said. In a poll of Republican insiders released by National Journal on Sept. 28, only 4 percent saw the party’s chances of winning control of the Senate as high. The poll called the outlook “a stunning drop in optimism” among Republicans.

Six Democratic incumbent women are leading in the polls: Claire McCaskill of Missouri, Maria Cantwell of Washington, Dianne Feinstein of California, Amy Klobuchar of Minnesota, Kirsten Gillibrand of New York and Debbie Stabenow of Michigan.

And Murray’s female recruits include three House members in competitive races: third-term Rep. Mazie Hirono of Hawaii, who was born in Japan and would be the Senate’s first female immigrant and first Asian-American woman; seventh-term Rep. Tammy Baldwin of Wisconsin, who would be the nation’s first openly gay senator; and seventh-term Rep. Shelley Berkley of Nevada, the granddaughter of immigrants who came to the United States, unable to speak English, to escape the Holocaust.