Six Iowans in Congress, all men, and it’s always been that way — but maybe not for much longer.

Of the five congressional races in Iowa, three women are contending for three seats. Women have run before but to no avail. However, this year has proven to be different.

From a pair of U.S. House hopefuls in Staci Appel and Mariannette Miller-Meeks to U.S. Senate candidate Joni Ernst, there’s a strong wave of optimism sweeping across the state among those voters hoping Iowa history will be made when a woman is finally sent to Congress — at least one of the three women is expected to win.

The perception among those following these historic elections is that Iowa, with its three female candidates, is ahead of the other three states — Delaware, Mississippi, and Vermont — to have never sent a female to Congress. Among them, Iowa is believed to be the only state to have a fighting chance at having a woman — or women — break the glass ceiling this November.

In this year’s Vermont and Mississippi elections, not one female candidate from either major party is on the November ticket. In Delaware, the lone Republican candidate is not expected to defeat a wildly popular Democratic incumbent.

But in Iowa, the power of incumbency, and the lack thereof, may have contributed most to the success of Iowa women finding spots on the November ballot. In three of the state’s five federal races, open seats arose after incumbents chose either to retire or seek a different seat.

Fourteen months after declaring her candidacy, Republican Ernst — a veteran currently serving in the Iowa Senate — remains neck and neck with Rep. Bruce Braley, D-Iowa, for retiring U.S. Sen. Tom Harkin’s seat. Appel, a former Iowa senator, is a Democrat vying for retiring Rep. Tom Latham’s 3rd Congressional District seat. And Republican Miller-Meeks is the only woman in this group facing an incumbent. The former director of the Iowa Department of Public Health is running against Rep. Dave Loebsack, D-Iowa, for the third time in Iowa’s 2nd Congressional District.

Recent polls have Ernst tied, Appel leading, and Miller-Meeks trailing in their respective races.

Jennifer Lawless, an associate professor of government at American University who has conducted research on why women don’t run for public office, said that while it’s a sign of progress, three Iowa females running for federal office doesn’t mean much when put into a broader context.

“It’s still a low number,” she said. “It’s a lot compared to one or zero. But, overall, across the nation, women are still a minority.”

Women make up 18.5 percent of the current Congress, with 79 women in the U.S. House and 20 women in the U.S. Senate — out of a total of 535.

Experts who study the role of gender in politics and elections provide a variety of arguments for why these four states, most of which have been progressive, have seen no female representation in Congress.

Vermont heralds its ratio of females in the state Legislature, which at 40.6 percent is the second highest proportion in the country.

Vermont residents can run a “pretty basic campaign” for not a lot of money and still get elected to state office, said Sarah McCall, the executive director of Emerge Vermont. But persuading and preparing women to make the jump, to raise sometimes hundreds of thousands of dollars, if not millions, for a seat in Congress can prove challenging.

The call for big money, coupled with the fact that Vermont’s elected officials have no plan of retiring any time soon, does not bode well for aspiring female politicians. Officials in Delaware, too, show no signs of retiring.

Republican Rose Izzo is running against Rep. John Carney, D-Del., who has held the seat since 2011. The race, however, is not getting much notice. Marian Palley, a professor emerita at the University of Delaware, who studies women’s involvement in politics, didn’t even realize a Republican was running in such a heavily Democratic state.

Palley said female candidates would have the best chance at success in a Democratic state such as Delaware if they waited until incumbents left office or retired.

This, Lawless said, is a reason fewer females become candidates.

“You can’t elect a woman if you don’t have a female candidate,” she said. “It’s not that women don’t run, it’s that there aren’t candidates.”