Last month, most of the 20 women who will serve in the Senate next year gathered in the Capitol for a meet-and-greet — and a show of strength.

Although it was a moment of celebration marking a historic number of women in the highest echelons of power, the confab produced another milestone: “For the first time, there was a traffic jam in the Senate women’s bathroom,” Sen. Amy Klobuchar (D-Minn.) later said — a comment that was widely reported.

Ladies’ room backups aside, some are wondering whether the record-breaking number of women will mean less gridlock, not more, in the chamber.

Women are more collaborative and collegial leaders, studies have found. And for those bemoaning the increasing nastification of the Senate, it may mean the chances for an antidote have just increased.

“We women set the tone for civility and respect on Capitol Hill,” said Sen. Barbara Mikulski (D-Md.), the chamber’s longest-serving woman. “We want to carry that tone of civility with us in an otherwise prickly institution.”

It’s not that the Senate’s women are less formidable than their male counterparts. Mikulski is known for her plain-speaking manner, and female leaders on the Hill, such as House Minority Leader Nancy Pelosi (D-Calif.) and Democratic Senatorial Campaign Committee Chairman Patty Murray (Wash.) — haven’t been afraid to throw an elbow.

But during a group interview with ABC’s Diane Sawyer set to air Jan. 3, the 19 female senators and senators-elect who were present agreed with Sen. Susan Collins (R-Maine) when she said, “I think if we [women] were in charge of the Senate and of the administration, we would have a budget deal by now.”

Across the Capitol in the House, a record 78 women will serve as representatives in the next Congress. But the impact in the smaller and more personality-driven Senate may be more evident: All six female senators facing reelection won, and five women are members of the freshman class.

“I think this is the most consequential aspect of the election,” said former Senate majority leader Thomas A. Daschle (D-S.D.). “Women bring the Senate an energy and a perspective and a potential for bipartisanship.”

For years, women in both parties have met regularly for dinners. Every few months, they meet in the Capitol’s Strom Thurmond Room, the irony of which isn’t lost on them. Their gathering spot is named for a man whose parting words to the Senate were, “I love all of you, and especially your wives.”

Over glasses of wine and sometimes a pecan pie baked by Sen. Mary Landrieu (D-La.), they discuss their personal worlds — kids, husbands, books, vacation plans.

“We talked about each other’s lives and stories,” said former senator Blanche Lincoln (D-Ark.).

They buy presents to celebrate milestones. When Collins got engaged, they threw a shower. The dynamic mimics the storied conviviality of the past, when Sen. Lyndon B. Johnson shared bourbon and small talk with friends and political enemies alike.

And, like then, the friendships can result in bipartisan legislation.

“Anytime I have tried to get things done and been successful, it’s been with the help of a Republican woman,” said Sen. Kirsten Gillibrand (D-N.Y.).

For example, in the 2010 fight to repeal the military’s “don’t ask, don’t tell” policy, she found an ally across the aisle in Collins. The duo were key in pushing through the bill heralded as an advance in gay rights.

The built-in network will now mean that even the most junior among them has the ear of nearly a quarter of the Senate. “When you have 20 people — not that they’re a monolithic bloc — but they’re more likely to hear you out on something,” says Sen. Olympia J. Snowe (R-Maine), who is retiring this year and has noted her frustration with the overall erosion of bipartisanship in Washington. “They will give you their every consideration, even if they don’t ultimately give you their support, which is all you can ask for.”

Female lawmakers say they simply may legislate differently from men.

Gillibrand recalled a hearing during her tenure in the House that focused on military readiness. She and some of the women on the House Armed Services Committee, including then-Rep. Gabrielle Giffords (D-Ariz.), inquired about supplies and personnel — and about mental-health programs for troops returning from combat.

“For us, it wasn’t just ‘How many guns?’ or ‘How many troops?’ ” she said. “And so out of that discussion came a fuller discussion that ultimately led to a better bill.”

Most of the Senate’s women are Democrats (16 of the 20 in the next Congress) and so the potential for bitter disagreement is diminished. But even when it’s opposing parties with opposing policy views, civility often survives.

For example, on the same day that Sen. Kelly Ayotte (R-N.H.) met with U.N. Ambassador Susan Rice and raised “serious concerns” about her possible nomination to become secretary of state, her Democratic colleague Jeanne Shaheen (N.H.) appeared on MSNBC to support Rice (and made a point to call Rice’s critics “patriots”). Two days later, the duo co-hosted an intimate Capitol Hill reception memorializing New Hampshire’s late senator Warren Rudman. (On Thursday, Rice withdrew her name from consideration.)

“Even though we may not see eye to eye on every issue, Senator Ayotte and I understand that it is in the best interest of New Hampshire to not let partisanship stand in the way of getting the job done for our state,” Shaheen said.

Still, Jennifer Lawless, director of American University’s Women and Politics Institute, cautions not to invest too much in the gender divide.

The women of the Senate may be quite similar to their male colleagues.

Anyone battle-tested enough to become a senator and to have faced the crucible of high-dollar fundraising and at least one statewide campaign is likely to have similarities and be wealthier, more aggressive and more confident than your average Joe (or Jane).

“Once you get to the Senate, you’re talking about people who are far more like one another than they are like the general populace,” she said.

Besides, Lawless said, there may not be enough women anyway for major change. Having 20 women in the Senate may seem like a lot, but it isn’t, she said.

The United States, which has 19 percent of congressional seats held by women, lags behind other countries, including Germany (34 percent), Canada (29 percent) and even Rwanda (52 percent) and Andorra (50 percent).

If the Senate ever reached those percentages, it’s safe to say the institution would change, at least in one regard: There would be even more traffic in the ladies’ room.