It shouldn't be surprising that it took more than 200 years for Congress to select a female speaker of the House. The United States isn't exactly at the forefront when it comes to women in politics.

Women make up a larger share of the national legislature in 79 other countries, including China, Cuba, North Korea and Vietnam, according to the Inter-Parliamentary Union, an association of national legislatures. The U.S. even trails a couple of fledgling democracies: Afghanistan and Iraq.

"When my colleagues elect me as speaker on Jan. 4, we will not just break through a glass ceiling, we will break through a marble ceiling," said Rep. Nancy Pelosi, who is set to lead the House when the Democrats take over. "In more than 200 years of history, there was an established pecking order — and I cut in line."

There were 22 women in the House when Pelosi was first elected to her California district in 1987. There will be a record 71 female representatives when she takes over as speaker, giving women 16 percent of the seats.

"The biggest obstacle women candidates face is not about gender, it's about the lack of opportunity," said Ellen R. Malcolm, president of EMILY's List, which helps Democratic women who favor abortion rights get elected to public office. "Ninety-eight percent of incumbents who run for re-election are re-elected in most years. ... The bottom line is there are very few opportunities."

Once women decide to run for office, they are just as successful as men, according to experts who study the issue. However, women are much less likely to run.

One big reason is child care. Women are much more likely than men to be responsible for child care, and that doesn't always fit into the usually chaotic schedule of a member of Congress.

"All these women, even if they are extremely qualified, they are still so much involved in their family life they couldn't even consider running for office," said Richard Fox, professor of political science at Union College in New York.

Fox did an extensive survey of women in professions that produce many lawmakers: education, business and the law. He worked on the study with Jennifer Lawless, an assistant political science professor at Brown University who ran for Congress this year, losing the Democratic primary in Rhode Island to incumbent Rep. James Langevin.

Among their conclusions:

—Women are less likely than men to be asked to run for office by party leaders and other officials.

—When women are asked to run, they are just as likely as men to do it.

—Women are more likely than men to think they are unqualified to serve, even when they have the same qualifications as male candidates.

"A man can wake up one morning, look in the mirror and say, 'By God, I would be the best state legislator that Nebraska has ever seen,"' said Debbie Walsh, director of the Center for American Women and Politics at Rutgers University. "Men don't need to be asked."

Rep. Jeanette Rankin, R-Mont., was the first woman elected to Congress, in 1916, four years before the 19th Amendment gave women the right to vote (women could already vote in Montana).

Before 1970, more than 40 percent of the women in Congress gained office by succeeding their dead husbands. Since then, fewer than 10 percent have followed their husbands, according to data collected by Dennis Simon, a political science professor at Southern Methodist University.

The number of women in Congress has grown slowly, with the biggest jump coming in 1992, the "Year of the Woman," when it nearly doubled, to 54.

Pelosi, 66, grew up in politics as the daughter and sister of Baltimore mayors. But she waited until her youngest daughter was in high school before she ran for Congress, a path followed by many women.

Women are, on average, older than men when they are first elected to Congress, giving them less time to rise in leadership, which is based largely on seniority.

Lena Saradnik was elected in November to the Arizona State Legislature for the first time at age 59. She said it would have been tough to run for political office while her daughter, now 30, was still young.

Saradnik, a Democrat from Tucson, said she could see herself joining Pelosi in Congress some day, but she's realistic about her prospects.

"If I were younger, I would probably say, absolutely," Saradnik said.

Saradnik said she decided to run for office after being approached by a local Democratic official. She was helped by a training program called Emerge America, which teaches public speaking, fundraising and media skills to female Democrats. Republicans have a similar programs called the Excellence in Public Service Series.

Marya Stark, executive director of Emerge America, predicted that more women will be inspired to run for office with Pelosi serving as speaker and Sen. Hillary Rodham Clinton, D-N.Y., being a potential candidate for president.

Pelosi embraces her role as the first female speaker, but she wants to be judged by the same standards as the 51 men who came before her.

"I have always asked my colleagues to judge me by the quality of my leadership and the results we achieve together, not as the first woman," Pelosi said.

But, she added: "Becoming the first woman speaker will send a message to young girls and women across the country that anything is possible for them, that women can achieve power, wield power and breathe the air at that altitude. As the first woman speaker of the House, I will work to make certain that I will not be the last."